M ' 


ELEMENTS  OF  PHOTOGRAVURE 


A SELECTION  OF 


LOCKWOOD’S  MANUALS 


Arithmetic  of  Building 
Art  of  Building 
Brick  and  Tile  Manufacture 
Bricklaying  ... 

Brickwork 
Builders’  Accounts 
Cabinet  Maker’s  Guide 
Carpentry  and  Joinery 
Clock  Repairing  and  Making 
Cotton  Industry 
Damp  Walls  ... 

Electric  Light  Fitting 
Electro-Plating 
French  Polishing  and  Enamellin 
Gas  Meters 

Gasfitting  and  Appliances 
Handrailing  and  Staircasing 
House  Painting,  Graining,  Etc 
Land  Ready  Reckoner 
Lathe  Work  ... 

Marble  Decoration 
Mechanical  Dentistry 
Metal  Plate  Work 
Plastering 

Plumbing  (Two  Vols.)  ... 

Roof  Carpentry 

Steel  Square  and  Roofing 

Superficial  Measurement 

Upholstering  and  Cutting  Out 

Valuation  Tables 

Watch  Repairing  and  Cleaning 


Dobson 

Allen 


2/6 
net  6 /- 


Searle 
Hammond 
Walker 
Keen 
Bitmead 
Tredgold 
Garrard 
Crabtree 
Blake 
Urquhart 
Watt 
Bitmead 
Gilbert 
Briggs 
Collins 
Davidson 
Arman 
Hasluck 
Blagrove 
Hunter 
Barrett 
Kemp 
Blake  each  6 /- 
Colli  ngs  net  2 /6 


7/6 
2 /6 
2 /6 
5/- 
3/6 
6/- 
6 h 
6/- 
8/6 
57- 
5/- 
2/6 
7/6 
6 h 

3/6 
7/6 
4/- 
6 /- 
3/6 
6 /- 
3/6 
37- 


Draper 

Hawkins 

Bitmead 

M’Caw 

Garrard 


2/6 

4/- 
2 /6 

5/- 

6/- 


Additional  volumes  in  this  Series  are  constantly  being 
published.  Latest  list  will  be  sent  on  application. 


CROSBY  LOCKWOOD  & SON. 


PHOTOGRAVURE  PRINT, 


Printed  with  Dark  Sepia  Photogravure  Ink 
No.  18192  by  Lorilleux  <£•  Bolton.  Ltd. 


ELEMENTS  OF 

PHOTOGRAVURE 

Photo  Printing  from  Copper  Plates 

Screen  photogravure  simply  explained 
with  full  working  instructions  and  an 
explanatory  chapter  on  modern  rotary 
gravure  printing 

A book  of  practical  interest  to  all  enthusiastic 
Photographers , Printers  and  Etchers 


By 

COLIN  N.  BENNETT 

F.C.S.,  F.R.P.S. 

TECHNICAL  ADVISER  TO  “ THE  BIOSCOPE  ” 


SECOND  IMPRESSION 


BOSTON,  U.S.A. 

AMERICAN  PHOTOGRAPHIC  PUBLISHING  CO., 

428,  NEWBURY  STREET,  BOSTON  17,  MASS. 

LONDON 

CROSBY  LOCKWOOD  & SON 
1927 


PRINTED  IN  GREAT  BRITAIN  BY 

THE  LONDON  AND  NORWICH  PRESS,  LIMITED,  ST.  GILES*  WORKS,  NORWICH 


THE  GETTY  RESEARCH 
INSTITUTE  LIBRARY 


PREFACE 


The  greater  part  of  the  contents  of  this  little  book 
made  its  first  appearance  as  a series  of  articles  in  the 
“ British  Journal  of  Photography  ” during  the  early 
months  of  1925.  About  the  same  time,  greatly  daring, 
I delivered  a lecture  on  photogravure  before  the  Royal 
Photographic  Society,  hoping  against  hope  that  experts 
would  kindly  keep  away  on  that  night.  However,  for 
my  sins,  they  did  not  do  so,  and  you  may  imagine  my 
heightened  nervousness  when  such  audience  as  there 
was  turned  out  to  be  composed  mostly  of  those  who 
knew  more  than  I.  That  they  treated  my  remarks 
kindly  and  found  therein  no  sufficient  reason  for 
(technically)  tearing  me  into  shreds  may  further 
justify  passing  on  knowledge  given  forth  at  that  time 
together  with  what  more  has  been  collected  during 
intervening  months  of  inky  enthusiasm.  Photo- 
gravure as  a direct  photo -printing  process  is  really 
wonderful,  a method  combining  truly  photographic 
precision  of  outline  with  the  inimitable  velvety  shadows 
and  tonal  values  of  a finely  proofed  etching.  Nor  is 
photogravure  complicated,  or  expensive  in  material, 
and  if  it  calls  for  careful  working  is  not  this  also  an 
advantage  ? Who  among  true  well-wishers  of  the 
craft  of  illustration  would  feel  drawn  toward  the  pro- 
duct of  sloppy  workmanship  ? 

COLIN  N.  BENNETT. 

1,  Cambridge  Place, 

Paddington,  London. 


CONTENTS 

PAGE 

Introductory  chapter  .....  1 

General  survey  of  the  process  ....  3 

Materials  required  . ■ . . . . 8 

Negatives  for  photogravure  . . . .17 

Preparation  of  the  positive  . . . . 19,  25 

Its  make  up  for  printing  the  resist  . . .21 

Tissues  for  resist  and  their  sensitising  . . 26,  37 

Screening,  its  method  and  the  function  of  the 

screen  ruling  . . . . . . 7, 40 

Illuminants  for  screening .....  40 

,,  ,,  sunlight  .....  42 

,,  ,,  electric  arc  light  . . .53 

,,  ,,  collimated  incandescent  light  .50-55 

Transparency  printing  . . . . .43 

Developing  the  resist  . . . . .57 

Making  up  for  etching  . . . . .62 

Etching  baths  and  their  characteristics  . .69,77 

Etching  by  multiple  baths  . . . .75 

An  alternative  simplified  etching  method  . . 93 

The  etched  plate.  Cleaning.  Appraising. 

Touching  up  . . . . .89 


viii 


CONTENTS 


Printing.  The  press 

PAGE 

. 103 

Inks,  paper,  materials 

. 107-9 

Soaking  of  paper  in  relation  to  its  surface 

. 108 

Papers  classified  .... 

. 106 

Characteristics  of  inks 

109,  119 

How  to  pull  a proof 

. Ill 

Toned  proofs  and  natural  proofs 

. 112 

Rotary  as  distinct  from  flat  plate  gravure 

. 116 

Special  problems  of  rotary  gravure  and  how  they 

are  met  . . . . . . .117 

The  cylinder  and  cylinder  etching 

.124-5 

Replacement  of  rag  wiping  with  the  “ 
blade  ” . 

doctor 

. 118 

Characteristics  of  paper  and  ink  for  rotary 

gravure  . . . . . . 119-121 

A simple  gravure  machine  and  its  working  . 128 


CHAPTER  I 


Introductory. — The  many  advantages  of  photogravure , 
whether  as  a photographer' s direct  printing  process 
or  as  a process  of  photo-reproduction , with  a brief 
general  survey  of  how  it  is  done. 

At  the  present  time  very  few  photograj)hers  work 
photogravure.  Nor  do  they  know  anything  about  it 
except  that  it  is  a photo-mechanical  process  made 
use  of  in  the  ink  printing  trade  for  finer  reproduction 
work  than  can  be  obtained  in  any  other  Avay.  Ask 
the  same  man  who  explains  this  to  you  what  Bromoil 
transfer  is,  and  he  will  inform  you  it  is  an  exceptionally 
flexible  and  controllable  method  of  direct  photo- 
graphic printing.  The  truth  is,  Bromoil  transfer  and 
photogravure  are  equally  photo-mechanical  repro- 
duction processes  or  direct  photo-printing  processes, 
according  as  you  choose  to  accept  them.  The  one,  we 
photographers  have  re -christened  (its  original  names 
were  brush-inked,  grainless  collotype,  and  collotype 
photo -litho  transfer)  and  have  taken  it  to  our  arms 
in  its  new  dress.  The  other  we  have  not  re -christened, 
for  the  simple  reason  that  we  have  not,  as  a body, 
realised  its  enormous  adaptability  to  our  uses.  My 
aim  in  writing  the  directions  which  follow  is  to  open 
photographers’  eyes  to  splendid  possibilities  we  are 
neglecting  by  leaving  photogravure  solely  in  the  hands 
of  the  book  and  magazine  trade. 

1 


2 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


Before  I go  further,  however,  it  is  only  fair  to  ex- 
plain how  I came  by  whatever  of  the  practice  of 
photogravure  I know.  Some  part  I puzzled  out  for 
myself.  The  rest  was  dug  out  of  printed  notes  and 
added  to  by  such  oral  hints  as  I could  muster.  The 
first  and  greatest  help  came  of  studying  Denison’s 
unique  (and  out  of  print)  work  on  the  subject,  not- 
withstanding that  Denison  has  no  mention  of  modern 
screen  photogravure,  but  deals  only  with  the  dust 
grain  process.  Later  on  Mr.  Rouse,  of  the  Autotype 
Co.,  Mr.  Laws,  of  Penrose  & Co.,  Ltd.,  and  Mr.  Kimber, 
all  helped  most  kindly.  As  a result  of  it  I have 
managed  to  piece  together  working  details  of  a pro- 
cess which  I am  confident  can  save  the  situation  for 
many  a man  who  in  the  past  has  tried  his  hand  at 
Bromoil  only  to  realise  that  it  is  not  nearly  so  much  a 
technical  printing  method  as  an  individual  gift  denied 
to  him.  Bromoil  transfer  is  pre-eminently  a process 
giving  broad  effects  which  are  never  twice  alike,  and 
which  call  for  fresh  expenditure  of  time  and  of  great 
skill  with  each  print  made.  Photogravure,  while  also 
permitting  enormous  individual  control  at  every  stage, 
makes  possible  effects  either  broad  or  detailed  at  will. 
Further,  it  possesses  the  outstanding  advantage  that 
the  printing  plate  holds  upon  it  a permanent  record 
of  the  photographer’s  skill.  Once  his  plate  is  as  he 
wants  it,  it  prints  the  same  again  and  again  over 
editions  of  hundreds  or  thousands  without  further 
question,  except  when  controlled  for  some  special  or 
varied  effect. 

Photogravure  prints  are  true  continuous  tone  photo- 
graphs built  up  of  varying  depths  of  ink  deposited  upon 
ordinary  paper  of  any  sort  or  kind.  They  have 


AN  INTAGLIO  PROCESS 


3 


nothing  whatever  in  common  with  half-tone  newspaper 
illustration,  and  can  easily  be  turned  out  indistinguish- 
able from  silver  prints  or  platinotypes  if  desired. 
When  worked  along  the  lines  I shall  describe,  very 
little  apparatus  is  required  for  photogravure  in  addi- 
tion to  a photographer’s  usual  equipment.  As  a com- 
mercial photographic  printing  process  for  editions 
between  fifty  and  a thousand,  photogravure  will  un- 
doubtedly prove  the  true  missing  link  between  good 
silver  printing  and  the  best  class  of  photo-reproduction, 
while  giving  a subtle  tonal  quality  not  present  in  any 
other  photo -printing  process  at  all. 

Now  to  make  a start  with  the  process  itself.  First 
I had  better  give  a brief  outline  of  what  text-books 
euphoniously  call  the  “ modus  operandi,”  after  which 
we  will  begin  to  collect  necessary  materials.  Well, 
then,  photogravure  is  an  intaglio  (pronounced  intarlio) 
copper-plate  process,  which  means  that  prints  are 
taken  by  pressing  damp  paper  heavily  down  upon  an 
inked  copper  plate  which  has  previously  been  etched 
to  a depth  corresponding  with  the  depth  of  tone,  or 
amount  of  ink,  to  be  transferred  to  the  paper  at  any 
given  point.  The  usual  method  of  getting  printing 
ink  into  the  copper  plate  is  first  of  all  to  smudge  the 
ink  promiscuously  all  over  the  surface,  then  to  wipe 
it  gently  and  evenly  with  special  wiping  cloths  till 
ink  only  remains  in  the  minute  hollowed-out  portions 
of  the  metal,  the  flat,  polished  top  of  the  plate  being 
once  more  clean,  as  if  it  had  never  been  inked  at  all. 
The  word  “ intaglio  ” stands  in  the  printing  industry 
to  signify  that  ink  is  transferred  from  hollows  in  the 
metal  to  the  paper,  and  not  from  raised  portions  of 
the  metal,  as  in  typographic  printing. 


4 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


Before  one  of  these  intaglio  copper  plates  can  be 
printed  from,  it  has  to  be  made.  That  is  done  by 
first  of  all  laying  down  upon  the  bare  copper  a “ resist  ” 
permeable  to  a suitable  etching  fluid  in  proportion  to 
the  shadow-printing  depth  of  the  original  negative 
which  controlled  the  resist  in  the  making.  In  screen 
photogravure  the  actual  substance  of  the  resist  is  a 
thin  film  of  gelatine,  and  the  way  of  getting  it  on  to 
the  copper  and  of  arriving  at  the  density  graduation 
necessary  to  give  us  our  controlled  etching  values  is 
not  unlike  ordinary  single  transfer  carbon  printing. 
So  here,  at  any  rate,  photographers  find  themselves 
up  against  nothing  radically  off  the  beaten  track.  At 
the  same  time  certain  more  minute  details  are  quite 
different,  and  at  the  outset  be  it  said  of  photogravure 
that  the  great  necessity  is  exact  attention  to  detail 
procedure  if  creditable  results  are  to  be  secured. 
While  the  routine  is  by  no  means  difficult  or  over- 
intricate,  you  can  “ slop  ” nothing  at  all  without 
paying  for  it  very  dearly  indeed.  So  the  slap -dash 
worker  may  at  once  take  the  hint  and  either  mend  his 
ways  or  give  this  most  beautiful  process  a wide  berth. 

I have  said  that  depth  of  etching  of  the  copper 
plate  decides  the  amount  of  ink  to  be  deposited  on 
the  paper  when  we  come  to  proof  printing.  Again, 
the  depth  of  gelatine  forming  the  photographic  resist 
we  first  lay  down  on  the  copper  determines  the  extent 
of  etching.  Therefore  it  must  follow  that  parts  of 
the  plate  covered  by  the  thinnest  resist  film  will  be 
those  which  will  give  rise  to  the  deepest  shadow  tones 
in  photogravure  prints.  In  carbon  work  the  thinnest 
gelatine  films  are  those  left  after  development  where 
light  action  has  been  least,  so  that  if  we  were  to  use 


THE  DI A POSITIVE 


5 


a negative  to  print  our  photogravure  resist  from,  we 
should  get  a plate  which  on  proofing  gave  negative 
instead  of  positive  pictures.  What  has  to  be  done, 
on  this  account,  in  photogravure  is  to  use  a positive 
as  the  “ negative  ” for  the  gravure  resist  printing. 
This,  while  it  involves  another  step  in  the  total  pro- 
cedure of  plate  preparation,  at  the  same  time  affords 
us  an  invaluable  advantage  in  that  we  may  introduce 
into  this  intermediary  positive  any  control  methods 
we  may  find  desirable,  and  whatever  benefit  they  give 
rise  to  will  be  faithfully  carried  over  to  the  final 
result  on  the  proofing  paper. 

Here  I may  mention  one  of  the  minor,  but  I think 
important,  detail  modifications  I have  preferred  in 
adapting  photogravure  to  the  photographer’s  immedi- 
ate needs.  The  accepted  method  of  positive  making 
for  resist  printing  is  by  the  use  of  a particular  gravure 
tissue  known  as  171  diapositive  tissue  in  the  Autotype 
series.  This  tissue  is  excellently  adapted  to  working 
from  copies  when  printing  by  contact  from  large 
negatives.  A simple  alternative  is  to  make  our 
printing  diapositives  upon  bromide  emulsion  plates  in 
the  projection  printer  or  enlarger,  merely  turning  the 
negative  about  so  that  the  glass  side  faces  the  easel. 

I have  talked  about  the  gelatine  resist  as  controlling 
depth  of  etching  of  the  copper  plate,  but  in  screen 
photogravure  it  does  more.  And  here  it  would  be  as 
well  to  differentiate  between  the  modern  “screen” 
and  the  old-fashioned  “ dust-grain  ” processes.  Her- 
bert Denison,  for  instance,  in  his  admirable  text-book 
tells  us  that  before  putting  down  the  carbon  trans- 
parency upon  the  copper,  the  plate  has  first  to  be 
grained  in  a dusting  box.  This  dusting  box  is  a large 


6 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


case  (about  the  size  of  a sugar  box)  having  a pivot  at 
its  middle  and  a stand  upon  which  it  can  swing  bodily 
round  like  a milk  churn.  About  three-quarters  of  the 
way  down  the  box  there  is  a shelf,  with  access  to  the 
shelf  through  a trap-door,  so  that  the  trap  can  be 
opened,  a copper  plate  slid  in  upon  the  shelf,  and  the 
door  closed  again  at  once.  The  way  you  used  the 
box  was,  roughly,  this  : You  put  inside  it  a quantity 
of  very  finely  powdered  bitumen,  and  proceeded  to 
make  the  box  fly  round  and  round  on  its  pivot  till 
the  whole  of  the  inside  was  one  cloud  of  bitumen 
dust.  Then  you  waited  a minute  or  two  (actual  timing 
was  highly  important)  with  the  box  stationary,  till  a 
certain  portion  of  the  heavier  bitumen  dust  motes 
had  settled,  and  then  you  slid  in  your  copper  plate 
upon  the  shelf,  and  again  timed  it.  On  withdrawing 
the  copper  it  would  have  a coating  of  fine  dust  particles. 
These  were  caused  to  adhere  to  the  metal  by  heating 
it  till  the  bitumen  went  glossy.  You  now  had  a plate 
wherein  alternate  microscopical  areas  of  the  metal 
were  left  bare  and  were  covered  by  spots  of  a substance 
— bitumen — which  is  resistant  to  the  etching  fluid. 
Later  on,  however  deeply  (within  reason)  the  plate 
was  etched,  these  minute  covered  portions  would 
remain  sticking  up  like  little  props  ; and  this  was 
actually  their  function.  They,  or  their  equivalent , 
have  to  be  present  on  every  photogravure  plate  to 
prevent  the  wiping  cloths  from  dropping  bodily  down 
into  the  etched  hollows  in  the  copper  and  wiping  the 
ink  out  of  them,  at  the  same  time  as  it  is  wiped  off  the 
bare  top  of  the  metal  (fig.  1). 

To  give  a homely  simile  : If  a boy  has  the  ill-luck 
to  drop  a penny  down  through  the  grating  of  an  area, 


GRAINED  AND  SCREENED  PLATES 


7 


he  cannot  get  his  penny  again,  not  because  the  area 
is  hermetically  sealed  by  the  grating,  but  simply 
because  the  bars  are  too  close  together  for  him  to  be 
able  to  get  down  between  them.  The  dust  grains  (or 
their  equivalent)  leave  on  the  printing  plate,  after 
etching,  a barrier  of  close-placed  copper  spurs  which, 
while  they  do  not  seriously  prevent  the  surface  of  a 
soft,  damp  piece  of  paper  from  dropping  down  between 
them  sufficiently  to  pick  up  the  ink  from  the  plate 


-vi  1 1 M 1 1 1 1 1 lixu-»^-uj.i  r 


Fig.  1. — Showing  section  of  etched  plate  with  screen  ruling  acting  as 
protection  for  ink  pockets  between 

hollows,  do  prevent  the  relatively  hard-faced  and  stiff 
wiping  cloths  from  doing  the  same  thing. 

All  the  same,  dust  graining  is  a very  delicate  bit  of 
technique,  and  grained  printing  plates  are  equivalently 
delicate  to  etch  and  to  proof.  In  modern  screen 
photogravure  the  same  thing  is  arrived  at  far  more 
sturdily  by  making  the  gelatine  resist  carry  a heavily 
printed  screen  pattern  in  addition  to  its  continuous 
tone  image  from  the  diapositive  (figs.  2 and  3).  Im- 
pressing this  pattern  upon  the  gravure  tissue  prior 
to  printing  upon  it  the  picture  to  be  rendered  in 
photogravure  is  called  “ screening.”  Hence  the  modern 
process  has  become  differentiated  from  dust  graining 
by  being  given  its  name  of  screen  photogravure . 


CHAPTER  II 


Materials  we  shall  want : screen  and  screen-printing 
frame,  tissue,  Beaume  hydrometer,  press,  and 
copper  plates  in  addition  to  the  usual  dark  room 
and  resources  of  a photographer . 

We  now  know  enough  of  the  general  outline  of  photo- 
gravure to  be  able  to  make  a rough  list  of  the  more 
important  (and  incidentally  more  expensive)  apparatus 
and  materials  needed  for  a trial.  In  that  way  we  may 
find  within  a little  the  cost  of  making  experiment — 
in  so  far  as  one  may  call  a process  an  “ experiment  ” 
wherein  the  result  of  reasonable  care  and  skill  will  be 
certain  success.  I assume  each  prospective  worker 
has  at  his  command  the  usual  resources  of  an  averagely 
well-appointed  dark  room,  including  an  artificial  light 
enlarger  or  projection  printer  ; water  supply,  and  some 
means  of  heating  water  ; also  electric  current,  which 
may  be  either  D.C.  or  A.C.,  and  of  any  voltage,  for,  with 
my  way  of  printing,  arc  light  is  not  a necessity.  As 
etching  troughs  for  copper  plates  ordinarily  enamelled 
iron  flat-bottomed  dishes  will  be  found  quite  satisfac- 
tory. Alternatively,  dishes  may  be  knocked  up  out  of 
any  odd  planks  of  wood,  afterwards  being  pitched  over 
inside  to  render  them  waterproof.  Of  course,  every 
photographer  will  possess  printing  frames,  but  here 
we  encounter  our  first  probable  expense  in  photogravure, 
for  you  cannot  be  sure  of  screening  at  all  a large  piece  of 

8 


PRESSURE  FRAMES 


9 


tissue  well  in  an  ordinary  printing  frame.  The  regular 
thing  for  this  is  a “ vacuum  frame  ” made  by  Messrs. 
Penrose  and  costing  in  the  15  by  12  size  £7  10s.  (fig.  4). 
However,  first  experiments  will  hardty  be  made  in 
sizes  much  above  7 by  5 inches,  for  which  a small 


Fig.  2. — Photo-micrograph  >of  actual  portion  of  a^st-ripped 
gravure  resist,  x 4-|  magnifications. 

pressure  frame  costing  about  thirty  shillings,  and  also 
obtainable  from  Messrs.  Penrose,  is  perfectly  suitable 
(figs.  5 and  6).  With  the  artificial  printing  light  I have 
devised,  or  using  bright  sunlight,  a worker  making 
experiments  with  plates  up  to  half -plate  size  or  there - 

B 


10 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


abouts  can  even  make  an  ordinary  printing  frame  do 
throughout  if  he  will  glaze  it  for  the  occasion  with 
a sheet  of  plate  glass  one-eighth  to  one-quarter  of 


Fig.  3. — Higher  power  micrograph  of  the  same 
printed  gravure  resist,  x 10  magnifications. 


an  inch  thick,  and  will  replace  the  usual  back  springs 
of  springy  brass  with  much  stronger  strips  of  mild  sheet 
steel,  increasing  the  strength  of  their  pivoting  screws 
in  proportion. 


COUNTING  THE  COST 


11 


So  there,  for  a start,  one  considerable  out-of-pocket 
expense  is  got  over.  The  actual  printing  light  arrange- 
ment for  an  all-weather  outfit  may  cost  anything  from 
almost  nothing  at  all  up  to  about  £3,  according  to  the 
number  of  accessories  going  to  make  it  up  which  can 
already  be  found  in  the  studio  or  dark  room.  I will 
leave  details  of  this  till  we  get  to  the  appointed  place 


Fig.  4. — Vacuum  frame  open.  Shows  : Front  glass  with  celluloid 

gravure  copy  screen  lying  on  it.  Frame  with  rubber  blanket  for 
backing.  Vacuum  pump  mounted  on  frame  back.  The  frame  is 
kept  open  by  an  ordinary  12-inch  meta]  rule,  seen  on  right,  to 
allow  of  inspection. 

for  them,  merely  saying  at  the  moment  that  the  great 
majority  of  photographic  establishments  will  already 
have  everything  neeessary  to  hand,  and  only  needing 
re-assembling  upon  any  available  free  table  or  work 
bench. 

That  brings  us  to  our  first  certain  and  considerable 


12 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


expense,  which  is  the  cost  of  the  photogravure  “ copy 
screen  ” itself.  My  own  one,  a very  nice  screen  on  a 
flexible  celluloid  base,  was  supplied  me  by  the  Autotype 
Company  at  the  price  of  £3  10s.  for  the  12  by  10  size. 
Other  sizes,  I understand,  are  priced  more  or  less  in 
proportion.  Penrose  offers  small  experimental  screens 
on  glass  at  a little  over  two  guineas  for  a size  of  approxi- 


Fig.  5. — Small  photo-mechanical  “ pressure  ” printing  frame, 
closed. 


mately  7 by  5 inches.  Probably  with  the  growth  of  a 
demand  for  such  small  photogravure  copy  screens  they 
would  soon  become  much  cheaper.  I have  just  heard 
that  the  Autotype  Company  supplies  an  8 by  6 celluloid 
screen  for  30s. 

Gravure  tissue  for  the  resist  costs  something  under 
£1  the  “band.”  As  you  can  buy  it  by  the  quarter 
band  or  alternatively  can  buy  it  in  ready-cut  pieces 


ODDS  AND  ENDS 


13 


the  same  as  with  any  other  grade  of  carbon  tissue, 
first  expense  of  trial  tissues  is  small. 

We  still  need  a few  things.  We  must  have  a thermo- 
meter, costing  a shilling  or  so,  an  accurate  Beaume 
hydrometer  (fig.  7)  with  testing  glass,  which  may  run 
into  half  a sovereign,  etching  fluid  (that  we  can  make 


Fig.  6. — Photo-mechanical  “ pressure  ” frame  open.  Shows  : Box  of 
frame  with  front  glass  ; cramping  strut  with  set  screw  ; back  of 
frame  ; blanket  to  go  inside  back  on  assembling. 

up  for  about  fourpence  a pint),  acid-resist  varnish, 
of  which  half-a-crown’s  worth  will  cover  our  needs  for 
months  to  come  and  some  copper  plate  ink.  Very 
good  quality  ink  can  be  had  in  four-ounce  tubes  at 
three  shillings  the  tube.  Those  of  us  who  have  tubes 
of  bromoil  ink  knocking  about,  that  we  would  like  to 
use  up,  may  ink  our  plates  with  it  instead,  and  will 
find  it  excellent. 


14 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


There  remain  the  actual  copper  plates  themselves 
to  be  bought.  Prices  of  these  vary  enormously  accord- 
ing to  the  firm  quoting  for  them.  Haddon  of  Salisbury 
Square  supplies  English-made  copper  (eighteen  gauge) 
at  an  approximate  price  of  one  shilling  for  each  twenty 
square  inches  of  surface.  A six  by  four-inch  plate  has 
twenty -four  inches  of  surface,  and  would,  therefore, 
cost  just  under  one  and  threepence.  Buying  by 
weight  the  price  works  out  at  about  three  shillings 
and  sixpence  a pound.  Kimber  supplies  copper  plates 
suitable  for  photogravure  at  much  the  same  rate  as 
this.  Both  the  above  firms  are,  moreover,  open  to 
sell  plates  in  quantities  as  small  as  the  buyer  may  wish 
even,  so  I understand,  a single  plate  at  a time.  For 
those  who  appreciate  the  hardest  of  hard  photogravure 
copper  and  who  have  progressed  beyond  the  experi- 
mental stage,  Penrose  is  a likely  source  of  supply  and 
the  copper  is  of  a thoroughly  satisfactory  grade. 
There  is  a saving  in  ordering  copper  plates  in  dozen 
lots  or  more  of  a size  from  the  firms  mentioned.  The 
Autotype  Company  supplies  also  a high  quality 
photogravure  copper. 

For  transparency  making  by  projection  I have  found 
nothing  to  beat  a backed  plate  coated  with  lantern-slide 
emulsion,  except  where  the  negative  worked  from  is 
excessively  soft.  Then  a process  plate  may  occasion- 
ally come  in  useful.  Ilford,  Ltd.,  supplies  plates 
in  any  size  coated  with  lantern-plate  emulsion,  and 
apparently  they  must  be  a stock  line,  for  they  nearly 
always  arrive  by  return  of  post.  Where  a negative 
has,  for  some  reason,  to  be  printed  by  contact,  use 
may  be  made  of  Imperial  “ stripping  ” process  plates. 
They  need  careful  handling  and  don’t  stand  for  too 


STRIPPING  PLATES 


15 


much  after-treatment,  being  in  some  ways  rather  like 
the  ordinary  plates  of  my  boyhood,  which  had  films 
that  let  you  know  when  they  had  been  dodged  about 
with  enough  by  incontinently  floating  away  from  their 
glass  support.  But  Imperial  strip- 
ping plates  are  all  right  if  you  go  at 
them  carefully.  When  dry  you  just 
lay  down  the  stripping  plate  trans- 
parency gelatinp  side  upward,  run 
a sharp  knife  along  the  coating 
one -eighth  of  an  inch  from  the 
edge  of  the  glass,  insinuate  the  tip 
of  the  knife  blade  under  one  corner 
of  the  gelatine  and  it  will  rise  and 
leave  the  glass  back  easily.  There- 
upon you  have  a very  thin  but 
tough  flexible  transparency  which 
may  be  printed  with  equal  sharp- 
ness from  either  side.  In  the 
directions  which  follow  I assume 
that  projection  printing  either 
with  enlargement  reduction,  or  to 
the  original  scale  will  be  our  more 
usual  practice. 

We  still  need  a copper  plate 
printing  press  and  supply  of  paper 
if  we  are  to  proof  our  own  plates 
(and  precious  little  fun  I for  one 
should  find  in  photogravure  if  I 
left  this,  the  most  exciting  part  of  it  all,  to  anyone 
else).  The  cheapest  price  I have  heard  quoted  for  a new 
copper  plate  press  capable  of  proofing  plates  up  to 
eight  inches  in  diameter  is  £6.  Such  a press  may  be 


Fig.  7. — Beau  me  hydro- 
meter and  testing  glass. 


16  PHOTOGRAVURE  FOR  PHOTOGRAPHERS 

had  from  W.  Kimber,  from  Newman  & Sinclair, 
or  from  Penrose,  to  mention  three  sources  which  come 
immediately  to  my  mind.  Second-hand  copper  plate 
presses  come  upon  the  market  from  time  to  time  at 
ridiculously  low  prices,  but  that  means  waiting  for 
them  and  seizing  your  opportunity  as  it  arrives.  Paper, 
on  the  other  hand,  will  worry  no  one  on  the  score  of 
expense  for  the  simple  reason  that  there  is  no  sort  of 
paper  whatever  which  cannot  be  made  use  of  for  proof- 
ing from  copper  plates.  Typing  paper  will  do,  so  will 
blotting  paper,  to  mention  in  the  same  breath  two  utter- 
most extremes.  It  is  all  a question  of  soaking,  which 
matter  can  now  wait  over  for  further  comment  when  we 
are  ready  to  tackle  it.  The  proofing  paper  I have  used 
mostly  of  late  costs  three -halfpence  a sheet,  each 
sheet  cutting  into  nine  pieces  approximately  ten  by 
seven  inches  in  size.  Compare  that  with  the  cost  of 
printing  bromides  of  the  same  or  equivalent  dimensions. 

Finalty,  in  computing  the  cost  of  fitting  up  apparatus 
and  providing  materials  for  first  steps  in  photogravure, 
suppose  we  allow  another  pound  note  for  odd  and 
incidental  expenses  ? Thus  we  shall  arrive  at  a reckon- 
ing which  places  our  full  bill  of  probable  costs  at 
something  between  ten  and  fifteen  pounds,  though 
great  care  and  strict  economy  might  keep  the  figure 
actually  below  the  ten  pound  mark. 


CHAPTER  III 


The  right  kind  of  negative  for  gravure  and  hints  on  how 
to  make  a suitable  printing  positive  from  it.  Making 
ready  the  positive  for  printing  gravure  tissue. 

The  best  type  of  negative  from  which  to  make  a 
projection  positive  for  direct  photogravure  is  an 
“ enlarging  ” negative,  and  a rather  thin  one  at  that. 
Bromoil  workers  will  need  little  further  guidance  at 
this  point,  for  a good  Bromoil  negative,  verging  slightly 
to  the  thin  side,  but  free  from  veil  and  with  plenty  of 
fine  shadow  detail,  will  also  be  found  just  right  as  the 
starting  point  of  photogravure.  In  my  own  experience 
— which  I put  forward  for  what  it  may  be  worth — it 
has  proved  a good  plan  not  to  embellish  this  negative 
with  much  in  the  way  of  hand-work.  Local  reduction  of 
the  sky  with  hypo  and  ferricyanide  reducer  often  helps 
cloud  rendering,  even  where  the  negative  has  been 
made  on  a panchromatic  plate,  using  a yellow  colour 
screen.  Also  I do  not  hesitate  to  build  up  shadow 
detail  locally  if  necessary  by  the  application  of  a one- 
solution  mercuric  iodide  intensifier  made  as  required  by 
dissolving  a dram  of  soda  sulphite  and  a grain  of  mer- 
curic iodide  in  an  ounce  of  water.  Exact  proportions 
of  these  constituents  are  somewhat  unimportant,  so 
that  in  practice  one  soon  gets  to  make  up  the  intensifier 
in  small  quantities  by  guesswork.  In  local  intensifica- 
tion it  is  necessary  to  remember  that  the  intensified 

17 


18 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


parts  of  the  negative  will  have  when  dry  considerably 
greater  printing  depth  than  hand  inspection  of  the 
same  negative  while  wet  would  seem  to  suggest.  A 
good  rule,  therefore,  in  local  chemical  treatment  of 
a negative  for  projection  positive  making  is  to  be 
less  afraid  of  slight  over-reduction  than  of  overdoing 
intensification.  Choked  up  high-lights  leading  to 
blank  white  areas  in  the  resulting  positive  are  to  be 
avoided  wherever  possible,  while  large  areas  of  detail- 
less  shadow  are  only  slightly  less  objectionable.  In 
both  local  intensification  and  reduction  the  solution 
is  applied  gently  on  a camel-hair  brush.  Use  the 
brush  rather  dry  where  small  areas  are  being  treated , or 
where  only  slight  action  is  wanted,  and  have  ready 
a dish  of  clean  water  or  preferably  a running  water  tap 
for  rinsing  the  plate  at  the  first  sign  of  the  reagent 
overrunning  its  appointed  part  of  the  image.  Over- 
intensification with  mercuric  iodide  can  be  removed  by 
immersing  the  negative  in  a clean  hypo  bath  of  moder 
ate  strength. 

So  far  we  are  going  over  old  ground  to  many  of  us. 
The  dry  negative  further  needs  to  be  spotted  with 
any  good  opaque  pigment  to  fill  up  pinholes,  but  here 
great  care  should  be  taken  to  do  the  spotting  as  neatly 
as  possible,  for  the  least  untidiness  will  make  trouble 
later  on. 

Where  the  entire  negative  is  over-dense  we  have  two 
obvious  ways  of  going  to  work  in  making  a photo- 
gravure positive  from  it.  We  can  either  reduce  the 
negative  first  of  all  with  ammonium  persulphate  or 
develop  the  positive  with  a soft-working  developer 
such  as  rodinal,  or  with  metol  to  which  has  been 
added  about  one-half  its  own  weight  of  hydroquinone, 


ENLARGED  DIAPOSITIVE  MAKING  19 

for  plain  metol  developer  gives  too  grey  a positive  to 
be  of  much  use  for  anything. 

The  negative  may  now,  optionally,  be  varnished, 
but  I have  not  found  advantage  from  the  application  at 
this  stage  of  retouching  medium  or  lead.  On  the  con- 
trary, it  always  comes  out  more  or  less  upon  the 
positive,  and  the  positive  in  due  course  hands  over  these 
traces  of  hand  finishing  to  the  printing  plate,  whereas, 
if  hand  work  is  held  over  t'o  the  positive  stage, 
the  printing  plate,  for  some  reason  or  other,  absorbs 
it  in  a true  blend  with  the  strictly  photographic  part 
of  the  image. 

Let  us  at  once,  therefore,  get  the  negative  in  the 
enlarger  carrier,  remembering  to  place  it  reverse  way 
round  so  that  the  image  on  the  easel  is  also  laterally 
reversed.  The  general  method  of  focussing,  exposing 
and  developing  the  transparency  is  as  usual  for  good 
enlargement  or  reduction  printing.  I make  a rule  of 
working  with  plates  coated  with  lantern-plate  emulsion 
(Ilford  Special  lantern)  and  invariably  order  them 
backed.  My  enlarger  is  of  the  condenser  type,  the 
llluminant  being  a gas-filled  focus  lamp,  but  between 
the  light  source  and  condenser  face  there  is  a sheet  of 
ground  glass.  The  enlarger  lens  is  a photographic 
anastigmat  (T.  T.  & H.  “ Cooke  ”)  of  very  good  defining 
quality  but  of  no  considerable  rapidity,  and  is  usually 
kept  at//ll.  Focussing  is  done  upon  a fogged  unde- 
veloped plate,  using  a magnifying  glass  of  just  sufficient 
power  to  allow  definition  of  the  silver  grains  to  be  used 
as  a focussing  guide.  When  the  transparency  is  to  be 
at  all  a large  one  I first  of  all  get  my  exposure  timing 
exactly  correct  by  cutting  a quarter  plate  coated  with 
the  same  emulsion  into  two  or  three  slips  in  steps  by 


20  photogravure  for  photographers 

placing  an  opaque  card  over  it  and  moving  the  card 
along  a short  distance  at  equal  time  intervals.  In  that 
way  each  next  greater  density  step  on  the  emulsion  will 
be  the  result  of  adding  one  more  timing  unit  to  the 
plate  exposure.  Thus,  if  our  units  are  to  be  five- 
second  ones,  shifting  along  the  covering  card  will  expose 
the  plate  in  equal  steps  representing  five  seconds, 
ten  seconds,  fifteen  seconds,  twenty  seconds,  twenty- 
five  seconds,  and  so  on.  The  beauty  of  this  grading 
method  is  its  unbeatable  simplicity,  for  with  it  you 
cannot  go  wrong.  There  is  no  need  to  remember 
multiples  or  special  progressions  and  no  need  to  be 
able  to  identify  independently  which  end  of  the  plate 
you  started  from.  After  development  you  simply 
take  out  the  slip,  count  along  to  the  density  you  like 
best,  and  the  density  count  is  your  count  of  time 
units  also. 

The  great  importance  of  exact  timing  lies  chiefly 
in  the  necessity  of  hitting  your  exposure  exactly 
and  developing  the  transparency  plate  right  out. 
Cut -short  development  leads  to  grey  sloppy  shadows 
and  running  together  of  the  finer  details  in  the  high- 
lights, both  fatal  defects  for  the  photogravure  worker, 
because  clean  high-light  detail  rendering  is  of  the 
essence  of  a good  printing  plate,  and  half-baked 
shadow  tones  in  the  plate  further  give  it  the  appearance 
of  being  worn  out  from  the  very  first  printing  im- 
pression. 

On  the  other  hand,  the  transparency,  while  being 
of  the  sparkling  order,  must  be  free  from  any  trace 
of  soot  and  whitewash.  No  part  of  it  need  be  of  greater 
density  than  we  would  aim  at  in  a not-over  dense 
lantern  plate  intended  for  use  as  a slide  in  actual 


AFTER  TREATMENT  HINTS 


21 


optical  projection.  While  small  points  of  high-light 
should  he  almost  clear  glass  the  next  thinnest  high- 
light may  be  even  slightly  over-emphasised,  for  the 
reason  already  implied — that  slight  flattening  here  is 
more  likely  to  be  found  in  the  finished  plate  than  in  the 
more  pronounced  mid-tones  and  shadows. 

Having  got  the  transparency  as  near  to  our  liking  as 
we  can  by  correct  exposure  and  complete  development, 
and  having  well  fixed  it  and  washed  it,  the  next  thing 
is  to  consider,  as  with  the  negative,  whether  good  can 
be  done  by  local  reduction  or  intensification,  or  both. 
This  time  we  may  with  advantage  err  rather  on  the 
heroic  side,  for  our  opportunity  has  fully  come  to  get 
a real  start  with  control  methods  and,  if  we  should 
unhappily  push  them  too  far,  after  all  it  only  remains 
to  prepare  another  transparency  and  try  again.  Any 
fair-sized  touches  of  light  we  may  help  with  the 
hypo-ferricyanide  reducer.  Cloud  forms  and  foliage 
may  call  for  judicious  touching  up  with  mercury 
iodide  intensifies  washing  the  plate  well  between  the 
two  treatments,  of  course.  After  mercuric  iodide 
applications  to  the  transparency  plate  it  is  necessary 
to  follow  a good  rinsing  with  a five -minutes’  soak  in 
normal  strength  M.Q.  or  similar  non-staining  developer 
prior  to  final  washing.  Otherwise  the  mercury-rein- 
forced part  of  the  image  will  be  coarse  and  brownish, 
and  will  not  blend  properly  with  the  untreated  part 
of  the  transparency  plate. 

Now  comes  the  time  for  hand  work.  My  way  is 
to  flow  the  gelatine  side  of  the  transparency  with 
“ Bildup  ” varnish  and  proceed  to  work  up  the  shadows 
with  as  soft  a lead  pencil  as  can  be  got  hold  of.  Nothing 
harder  that  6 B will  do  for  heavy  shadows,  but  2 B or 


22 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


3 B is  suitable  for  fine  detail  emphasis  in  the  light 
tones  or  for  filling  in  clear  glass  resulting  from  previous 
spotting  of  the  negative  with  opaque  pigment.  In  our 
first  trials  we  may  even  be  tempted  to  use  water  colour 
put  on  lightly  with  a sable -brush — but  only  the  first 
time.  Even  the  least  touch  of  pigment  comes  out 
later  on  as  a black  patch  on  the  photogravure  proof. 
However,  ink-black  shadows  can  be,  and  should  be, 
added  where  required  in  just  this  way. 

For  very  brilliant  small  patches  of  light  the  trans- 
parency may  be  “ shaved  55  with  a retouching  knife 
before  or  after  flowing  with  “ Bildup.”  First  of  all 
dry  the  plate  before  a fire  or  radiator  till  it  is  thoroughly 
warm,  then  pare  down  the  film , holding  the  knife  blade 
almost  parallel  with  it,  so  as  to  get  a razor  action. 
This  is  well-known  retouching  practice, 
jl  If  the  positive  then  appears  to  your  liking  it  may  be 
made  ready  for  printing  the  resist  by  bordering.  My 
favourite  way  of  bordering  is  not  by  affixing  opaque 
paper,  or  painting  out,  but,  on  the  contrary,  by  cutting 
through  the  gelatine  and  scraping  away  the  rim  between 
the  cut  and  the  plate  edge  (fig.  8).  Enough  rim  must 
be  removed  to  leave  the  picture  which  remains  of  the 
exact  dimensions  decided  upon  for  the  photogravure 
to  be  etched.  Above  all  things,  be  careful  that  removal 
df  the  unwanted  gelatine  is  done  cleanly  and  true  to 
shape.  The  simplest  aid  I have  so  far  discovered  to 
ensure  making  a good  job  of  transparency  border  mark- 
ing is  a plasterer’s  steel  T square.  It  is  flat,  and 
shaped  like  a draughtsman’s  celluloid  T square,  but- 
being  of  mild  steel  you  can  run  the  knife  along  its  edge 
without  throwing  it  out  of  truth.  These  T squares  can 
be  ordered  of  any  ironmonger. 


TRANSPARENT  AND  OPAQUE  BORDERING 


23 


^ What  is  to  my  mind  a strong  point  about  using  an 
accurately  transparent -bordered  positive  for  tissue 
printing  is  that  where  this  is  done  it  is  possible,  with 
careful  and  skilful  etching,  to  get  a gravure  plate  with  a 


Pig.  8. — Fcsitive^.  transparency  with  clear  scraped 
border  supported  on  retouching  desk. 

delicate  natural  boundary  line  to  the  picture,  a line 
somewhat  like  (though  distinct  from)  that  made  by 
artists  upon  hand-drawn  and  etched  copper  plates. 
An  alternative  and  in  some  ways  simpler  method 
is  to  follow  ordinary  carbon  printing  practice,  by  giving 
the  positive  an  opaque  “ safe  edge  ” of  tinfoil  or  thin 
black  paper.  Where  this  is  done  the  whole  work  of 


24 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


providing  suitable  limits  to  the  etched  area  of  the 
copper  depends  upon  a properly  controlled  application 
of  acid  resisting  varnish  to  the  copper  later  on,  after 
the  resist  has  been  developed.  That  will  be  dealt  with 
when  the  time  for  it  comes. 

I have  already  mentioned  a possibility  of  getting 
reversed  positives  by  contact  printing  through  using 
plates  coated  with  stripping  film.  Another  way  of 
arriving  at  the  same  result  in  a silver  printing  process  is 
by  using  cut  film — which  should  be  coated  upon  as  thin 
a celluloid  base  as  possible — and  resist -printing  with  the 
celluloid  side  next  to  the  tissue  in  the  printing  frame. 
This  simple  expedient  works  quite  satisfactorily  where 
there  is  a strong  concentrated  light  available  of  the  sort 
which  gives  rise  to  sharp  cast  shadows. 

By  far  the  most  widely  used  way  of  getting  a good 
gravure  diapositive  by  contact  printing  is  by  the  single 
transfer  carbon  process  itself,  using  diapositive  tissue 
171  and  transferring  on  to  thin  celluloid.  The  celluloid 
needs  no  special  preparation  whatever,  for  an  image 
printed  on  Autotype  171  tissue  has  the  property  of 
holding  on  to  it  without  requiring  the  usual  hard 
gelatine  substratum  generally  regarded  as  necessary 
in  single  transfer  carbon  work.  To  sensitise  this  tissue 
it  should  be  soaked  for  a couple  of  minutes  in  bichro- 
mate of  potash  solution  and  dried  in  contact  with  a 
glass  or  ferrotype  plate  in  the  way  that  will  presently 
be  described  for  preparation  of  gravure  resist  tissue. 
Development,  too,  is  similarly  with  hot  water.  Please 
read  the  description  to  be  given  of  the  way  to  put  down 
and  develop  a resist  upon  copper,  then  just  substitute 
celluloid  sheet  for  the  fully  prepared  copper  plate  and 
proceed  in  the  same  way,  with  this  imjDortant  exception. 


CARBON  TRANSPARENCY  MAKING 


25 


Do  not  use  any  methylated  spirit  with  the  water  in  which 
171  tissue  or  the  celluloid  sheet  is  placed , and  let  the 
developed  positive  dry  naturally  by  drainage , and  not 
by  dabbing , or  by  blowing  with  hot  air. 

Reversed  carbon  diapositives  so  made  are  full  of 
delicate  gradation  but  have  little  “pluck.”  Some* 
workers  find  them  all  the  better  for  that.  Others,  who 
would  rather  have  a steeper  range  of  contrasts,  can 
intensify  the  positives  easily  enough.  To  do  so,  let 
them  dry  first.  Then  prepare  a strong  solution  of 
potassium  permanganate  and  dip  each  positive  in  it. 
Strength  of  the  solution  is  not  very  material.  One 
dram  to  four  ounces  of  water  is  useful,  and  the  immer- 
sion need  not  be  for  more  than  half  a minute  or  so. 
Apparently  the  pigment  undergoes  an  oxidation  change 
which  greatly  deepens  its  colour  and  at  the  same  time 
turns  it  from  a rather  washed-out  purple -brown  to  a 
much  more  non-actinic  brown-sepia.  After  intensifica- 
tion, rinse  out  all  free  permanganate  and  hang  the 
diapositives  up  to  dry  again. 

With  our  transparency  plate  or  “ diapositive  ” made, 
worked  up  and  bordered,  we  are  ready  to  start  upon 
sensitising  the  “ gravure  ” tissue  and  getting  it 
“ screened  ” and  printed  for  putting  down  the  resist. 


CHAPTER  IV 


More  necessary  details  about  gravure  screens  and  their 
function.  The  correct  handling  of  vacuum  frames 
and  some  help  in  choosing  copper.  Different 
characteristics  and  behaviour  of  copper  plates. 

The  time  has  now  come  to  go  more  carefully  into  the 
question  of  materials  needed  for  preparing  the  gravure 
resist  and  getting  it  safely  down  on  the  metal.  Let  us 
take  these  in  their  order  of  appearance,  as  with  the 
actors  in  a West  End  theatre. 

The  standard  British  tissue  for  either  flat  plate  or 
rotary  screen  photogravure  is  Autotype  G 12.  It  is  a 
carbon  tissue  pure  and  simple,  lightly  impregnated 
with  burnt  sienna  pigment.  Several  other  gravure 
tissues  are  prepared  by  the  Autotype  Co.,  notably 
G 7,  wherein  the  pigment  is  brown  instead  of  reddish  ; 
G 14,  the  gelatine  of  which,  instead  of  having  a pigment 
colouring,  contains  an  aniline  dye,  and  G 15,  a tissue 
made  to  a special  formula,  which  aims  at  giving  greater 
control  of  etching  in  detail  in  the  high-lights.  Sensi- 
tising, printing  and  etching  directions  which  follow 
though  worked  out  primarily  for  G 15  and  G 12  tissue, 
apply  with  little  modification  to  the  others  also. 

Next  we  need  the  “copy  screen  ” and  a suitable 
screening  frame.  I can  best  describe  a copy  screen  by 
explaining  that  it  is  a photographic  contact  print  or 
“ copy  ” from  a master  screen  kept  in  the  hands  of  the 

26 


MASTER  AND  COPY  SCREEN 


27 


screen  makers.  The  master  screen  does  not  therefore 
directly  concern  us,  though  knowing  what  it  is  may 
help  us  to  understand  the  copy  screen  the  better. 
Well,  then,  a master  screen  is  made  by  ruling  a plate 
with  black  lines  equally  spaced  apart  and  crossing 
each  other  at  right  angles  (fig.  9).  The  width  of  each 


Fig.  9. ---Photogravure  master  screen  ruling,  much  enlarged. 

line  is  not  more  than  one-half,  and  may  be  as  little 
as  one-fourth,  the  width  of  the  spacing  between  it  and 
the  next  line.  (In  the  more  familiar  “ half-tone  ” 
screen  lines  and  spaces  are  of  equal  width.)  (Fig.  10.) 
Let  us  imagine  such  a photogravure  “ master  ” screen 
as  being  used  as  a negative  from  which  a contact 
transparency  is  made.  The  transparency  will  be  the 
copy  screen.  It  will  be  a right-angle  hatchwork  of 
transparent  lines  upon  a dead  black  opaque  ground, 
each  transparent  line  of  not  more  than  one-half  the 


28 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


width  of  the  adjacent  opaque  square  (fig.  11).  As 
previously  stated,  copy  screens  are  made  upon  either 
glass  or  celluloid.  Personally,  I prefer  celluloid, 
because  it  goes  more  snugly  into  a pressure  or  vacuum 
frame,  and  because  of  the  absence  of  any  steep  sharp 
edge,  and  its  comparative  thinness.  Standard  photo- 
gravure screen  ruling  is  150  lines  to  the  inch.  For 
very  fine  work  175  and  200  line  rulings  are  made. 


Fig.  10. — Enlarged  reproduction  of  ruling  of  ordinary 
typographic  half-tone  screen. 

Corning  to  the  screening  frame,  if  we  decide  to  start 
with  an  ordinary  photo-mechanical  worker’s  pressure 
frame,  this  is  a heavily  built  metal-braced  box,  fronted 
with  a slab  of  plate  glass  at  least  three-quarters  of  an 
inch  in  thickness.  The  back  of  the  frame  is  a sturdy 
hard-wood  board  strengthened  with  a plate  or  plates 
of  sheet  steel.  The  whole  is  completed  by  a removable 
screw  clamp  which,  after  the  back  of  the  frame  has  been 
lowered  into  place,  allows  of  it  being  forced  tightly 
up  against  the  front  glass  by  turning  one  or  more  screw- 
heads,  pressure  between  glass  and  back  of  frame  being 


SCREENING  FRAMES 


29 


controlled  exactly  after  the  same  style  as  when  screwing 
down  an  old-fashioned  letter-copying  press.  The 
regular  photogravure  “ vacuum  frame  ” is  a very 
different  thing.  It  is  comparatively  lightly  built  ; 
its  front  is  a^sheet  of  quite  thin  plate  glass,  and  its 
back  is  [made  of  rough-surfaced  india-rubber  sheeting 


■MMmmmwmsmmz 


•*s+*l**K*Z\~* 

%%%%%%%%%%!♦%!*%%% 


Fig.  11. — Photogravure  copy  screen  ruling,  much 
enlarged.  The  copy  screen  is  the  one  actually  used. 

rimmed  with  a deep  groove.  When  the  frame 
is  closed  a tongue  of  rubber  fitted  round  about 
the  edge  of  the  front  glass  engages  with  this 
groove  so  as  to  make  an  air-tight  joint.  Either 
attached  to  the  side  of  the  frame  or  supplied  as  a separ- 
ate unit  (according  to  the  frame’s  size)  is  a simple 
vacuum  pump  worked  like  a motor  tyre  inflator,  but 
arranged  to  suck  air  out  instead  or  forcing  it  in.  A 
flexible  tube  from  the  pump  goes  to  a union  in  the  back 
rubber  sheet  (called  the  “blanket.”  probably  because 


30 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


in  the  printing  industry  any  soft  backing  seems  to  be 
referred  to  as  a blanket). 

We  shall  by  now  appreciate  that  when  the  frame 
has  been  closed  the  action  of  working  the  vacuum 
pump  will  be  to  exhaust  most  of  the  air  between  its 
rubber  “ blanket  ” and  front  glass.  Upon  this  being 
done  atmospheric  pressure  acting  against  the  internal 
vacuum  brings  front  and  back  of  frame  together  under 
an  internal  pressure  not  much  short  of  the  theoretical 
fifteen  pounds  to  the  square  inch.  Thus,  without 
the  structure  of  the  frame  or  its  glazing  being  subjected 
to  any  breaking  strain  at  all,  screen  and  tissue  placed 
inside  will  have  a thorough  squeezing  together. 

Let  us  proceed  to  the  selection  of  copper  plates.  The 
first  thing  to  decide  is  what  size  plates  we  will  use.  I 
made  my  own  start  with  four-inch  by  three-inch  plates, 
an  obvious  merit  of  them  being  that  the  cost  of  early 
trials  w^as  thereby  kept  down  to  a proportionately 
small  amount.  Even  without  taking  particular  care 
to  buy  plates  of  this  size  in  the  cheapest  market,  they 
will  not  cost  more  than  sixpence  or  sevenpence  each. 

People  who  do  not  favour  very  small  work  can  start 
with  five  by  four-inch  plates,  costing  about  a shilling 
each.  I think  these  dimensions  approach  too  nearly 
to  the  square  to  be  ideally  proportioned,  but  a six 
by  four  sized  plate  is  excellent,  and  pulls  from  it  show 
up  well  on  mounts  measuring  as  much  as  ten  by  seven 
inches.  Also  you  can  print  a post-card  off  a six  by 
four -inch  plate  so  as  to  carry  the  picture  right  up  to  the 
margin  of  the  card.  Therefore  the  size  has  a double 
application.  Larger  plates  preserving  equally  pleasant 
relative  proportions  are  seven  by  five  (the  exact  dimen- 
sions of  a two-diameter  enlargement  from  a three  and  a 


THE  RIGHT  SORT  OF  COPPER 


31 


half  by  two  and  a half  negative),  ten  by  seven,  twelve 
by  eight,  etc.  To  make  a rough  estimate  of  the  cost 
of  any  sized  plate,  multiply  together  the  measurement 
in  inches  of  any  two  adjacent  sides  and  divide  by 
twenty,  the  approximate  answer  being  in  shillings  and 
fractions  of  a shilling. 

Plate  size  can  therefore  be  easily  settled  to  our 
satisfaction.  A far  more  important  question  is  that 
of  estimating  hardness  and  quality  of  the  copper.  For 
the  beginner  at  photogravure  this  is  the  worst  “ snag  ” 
lie  may  encounter.  Just  as  with  Bromoil  an  unlucky 
worker  sometimes  makes  his  first  attempts  with  a 
batch  of  paper  which  will  not  pigment  properly,  so 
may  the  Photogravure  tyro  chance  upon  copper  which 
is  over-soft,  or  of  bad  surface,  or  (worst  of  all)  copper 
which  to  the  inexperienced  eye  looks  all  right  but  suffers 
from  stress  veins  due  to  faulty  rolling.  The  latter  can, 
with  a little  practice,  be  recognised  if  you  catch  the  light 
reflected  off  the  metal  at  an  angle  from  the  polished 
side,  stress  marks  then  having  an  appearance  somewhat 
similar  to  those  variations  of  gloss  seen  as  narrow 
pathways  about  the  edges  of  a well  danced-over  ball- 
room floor.  When  you  notice  markings  like  that 
on  bright  copper  suspect  them  at  once.  If  the  mark- 
ings are  not  easily  removed  by  treatment  with  wet 
willow  charcoal  you  will  be  sure  they  are  going  to  affect 
the  etch,  and  a wise  man  will  turn  the  plate  over  to 
some  other  purpose  and  not  waste  good  time  and 
patience  with  it. 

Softness  or  hardness  of  the  copper  comes  next  in 
importance.  Though  both  grades  of  copper  will  etch, 
their  etching  characteristics  are  entirely  different. 
Thus,  experience  gained  with  a certain  degree  of 


32 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


hardness  does  not  hold  for  other  degrees  of  it.  On  this 
account  my  counsel  to  the  serious  beginner  is  to  select 
as  hard  a “ gravure  ” copper  as  he  can  get,  and  to  buy 
up  enough  plates  of  the  same  batch  to  give  him  time 
wherein  to  find  his  feet  before  a possible  necessity 
arises  for  revising  precious  details  of  his  etching  timing. 
One  simple  way  to  tell  hard  from  soft  copper  is  to  make 
a little  scratch  with  the  blade  of  a pocket  knife,  or  better 
with  an  etching  point,  upon  the  bach  of  the  plate. 
A man  accustomed  to  handling  copper  plates  can  gauge 
their  hardness  roughly  by  flicking  his  finger  nail  against 
the  metal  to  make  it  “ ring.”  The  brighter  the  note 
the  harder  the  metal.  Scratching  the  back  of  one 
plate  with  the  corner  of  another  plate  from  a different 
batch  will  give  rough  indication  of  which  copper  is 
the  harder. 

Even  now  we  have  not  done  with  the  necessary 
precautions  in  choosing  copper.  Not  all  plates  show 
the  same  etching  colour.  By  this  I mean  that  in 
attacking  the  metal  through  the  gelatine  resist  the 
etching  fluid  gives  rise  to  a gradual  colour  change. 
As  this  colour  change  is  the  etcher’s  chief  means  of 
knowing  how  the  “ biting  ” of  the  plate’s  printing 
surface  is  proceeding  his  control  of  etching,  more  especi- 
ally in  the  super-important  high-light  details — that 
is  to  say,  in  the  most  difficult  portion  of  the  plate — is 
about  proportional  to  the  visibility  of  the  etching 
colour.  How  much  of  the  final  etches  he  will  see  will 
again  be  determined  by  the  extent  to  which  the 
etching  colour  of  the  attacked  copper  contrasts  with 
that  of  the  semi-transparent  gelatine  resist  overlying 
it.  It  has  been  said  that  G 12  tissue  has  a burnt  sienna 
colouring.  Therefore  a plate  which  etches  black,  or 


IMPORTANCE  OF  HARD  COPPER 


33 


green-black,  beneath  this  resist  will  reveal  the  progress 
of  etching  far  better  than  will  a plate  which  etches 
red-brown.  For  red  etching  copper  G 7 (cold  brown) 
tissue  may  be  preferable. 

Some  of  the  staunchest,  hardest  gravure  copper 
I have  handled  has  etched  precisely  the  red-brown 
tint  which  has  made  sky  detail  and  high-light  detail 
formation  literally  impossible  to  keep  watch  upon  with 
a G 12  resist.  As  a sporting  proposition  for  the  man 
with  a little  experience,  this  copper  is  fine,  but  a 
black-etching  sample,  even  though  not  quite  so  hard, 
is  a more  practicable  proposition  for  the  beginner. 

Why  should  hard  copper  be  so  important  in  photo- 
gravure ? For  two  reasons.  The  first  one  is  that, 
with  soft  copper,  etching  is  apt  to  “ bolt,”  as  it  were, 
and  so  rush  out  of  the  worker’s  control  in  the  final 
baths,  just  when  strict  control  is  most  necessary  to 
avoid  flattening  down  the  printing  quality  of  the 
plate  by  creating  a “ tone  ” over  the  highest  lights. 
The  second  reason  for  hard  copper  has  to  do  with  inking 
the  plate  for  printing.  Remember,  the  ink  has  first 
of  all  to  be  forced  down  into  the  minute  hollows  etched 
out  in  the  metal.  Afterwards  excess  of  ink  must  be 
wiped  off  the  surface  of  the  plate  before  each  impression 
is  pulled  from  it.  Both  wiping  operations  involve 
friction,  and  both  leave  a loophole  for  minute  particles 
of  gritty  dust  to  get  somehow  upon  the  wiping  cloths. 
With  soft  copper  the  least  accidental  scraping  of  the 
plate’s  surface  with  grit  will  cause  ruts  deep  enough 
to  hold  ink  and  print  as  hair-like  scratch  lines.  Even 
very  hard  copper  is  not  immune  from  the  fear  of 
scratch  markings,  but  it  is  more  so  than  soft  copper. 


CHAPTER  V 


In  which  a carbon  'printing  actinometer  is  described, 
minor  materials  are  got  ready  and  we  proceed  to 
sensitise  gravure  tissue. 

Or  minor  accessories  for  gravure  tissue  printing  the 
most  important  is  an  actinometer,  the  one  most 
general  being  named  the  Sawyer  actinometer.  It  costs 
only  a few  shillings,  and  is  exceedingly  simple  and  quite 
accurate  enough,  although  I cannot  honestly  say  it  is 
an  instrument  of  precision.  The  Sawyer  actinometer 
is  a japanned  tin  case  about  three  inches  long  and  one 
inch  wide  and  deep.  Its  front  carries  a glass  strip 
bearing  a series  of  graded  and  numbered  density  steps. 
Behind  the  graded  grass  is  provision  for  a narrow'  roll 
of  sensitive  albumenised  paper  (fig.  12).  The  roll  can 
be  pulled  out  as  required  to  make  a strip  of  the  sensitive 
paper  lie  against  the  graded  actinometer  glass  when  the 
frame  is  closed.  On  either  side  of  the  strip  runs  a 
rim  of  “ test  tint,”  of  sickly  plum-pink  colour.  An 
element  of  chance  lies  in  that  test  tint,  for  not  once  in 
ten  times  does  the  albumenised  paper  darken  to  match 
it.  In  fact,  so  far  as  colour  is  concerned,  albumenised 
paper  hardly  ever  repeats  itself,  being  very  sensitive 
to  atmospheric  changes  Therefore,  there  happens  to 
be  one  way  only  of  using  the  Sawyer  actinometer 
correctly,  which  is  to  judge  the  matching  of  printing 
depth  and  test  strip  with  the  whole  thing  held  well 
out  at  arms’  length.  In  that  way  failure  of  colour 

34 


DRYING  TISSUE  WITH  GOOD  SURFACE 


35 


matching  is  no  longer  obtrusive,  while  comparison  of 
the  test  paper’s  printing  depth  with  the  edges  of  the 
standard  tint  can  still  be  made.  Refills  of  albumen- 
jsed  paper  for  the  Sawyer  actinometer  should  be  stored 
in  a calcium  tube  or  storage  tin  if  they  are  to  be  kept 
for  a considerable  time 
prior  to  use. 

Unlike  ordinary  car- 
bon tissue,  gravure  tis- 
sue must  be  dried  after 
sensitising  by  squee- 
geeing it  against  a flat 
surface,  though  not 
necessarily  against  a 
glazed  surface.  Also, 

it  is  not  advisable  to 
use  a waxing  compound 
or  solution  on  the  sur- 
facing board,  or  plate, 
as  it  may  prejudice  the 
adherence  of  the  resist 
to  the  copper  later  on. 

Either  plate  glass  or 

ferrotype  is  suitable  for 
drying  tissue  with  a 

glazed  surface,  while  12.— Sawyer  actmoineter  open, 

, ' showing  : front  swung  on  its  hinge, 

matt  pulp  board  or  finely  disclosing  test  paper  and  test  tint. 

matted  ebonite  will  do 

if  an  unglazed  surface  is  preferred.  Workers  in  the 
trade  mostly  use  the  glazed  tissue,  but  not  all  of  them, 
so  the  choice  is  in  our  own  hands.  In  my  small  way  I 
have  found  that  really  good  ferrotype  is  as  suitable  and 
simple  as  anything. 


36 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


In  the  instructions  which  follow  I shall  presume  that 
we  have  available  a portable  electric  fan  and  a small 
electric  fire  or  radiator.  Exact  size  or  pattern  of  either 
is  unimportant,  and  both  are  usual  items  of  equipment 
of  any  modern  studio.  We  need  also  the  following  : — 
Potassium  bichromate,  ammonia,  ordinary  whiting, 
small  amounts  of  chromic  acid  and  sulphuric  acid, 
calcium  storage  tin,  a block  of  American  soft  willow 
charcoal  for  copper  plate  surfacing,  chamois  leather, 
methylated  spirit,  a few  enamelled  iron  or  china  flat- 
bottomed  dishes  in  good  condition  with  the  glaze 
intact,  a flat  squeegee  and  a copper  plate  burnisher. 

The  burnisher  is  not  a machine,  as  was  the  old-time 
print  burnisher,  but  simply  a small  metal  tool  rather 
like  a stuggy  bradawl  (preferably  curved  at  the  end) 
polished  to  complete  bluntness  where  one  would  expect 
the  cutting  edge  to  be  (fig.  13).  It  is  used  on  the  flat  to 
press  down  the  burred-up  edges  of  small  scratches 
which  may  be  marring  the  surface  of  the  metal. 

There  is  j ust  one  standard  sensitising  bath  for  gravure 
tissue.  It  is  made  by  dissolving  one  ounce  of  potassium 
bichromate  in  forty  ounces  of  water  and  slowly  stirring 
in,  drop  by  drop,  ammonia  till  the  orange-coloured 
solution  turns  to  a pure  lemon  yellow.  You  can  know 
beyond  question  when  the  right  amount  of  ammonia 
has  been  added  because  at  the  same  time  as  the  colour 
change  is  complete  the  bath  takes  a faint  permanent 
smell  of  ammonia.  Slight  over -neutralisation  will  not 
matter,  but  it  is  wise  to  let  the  excess  of  ammonia  be  as 
little  as  possible.  I find  a most  handy  strength  for  the 
stock  ammonia  bottle  for  photogravure  is  half  and 
half  of  the  “ liq  : ammon  : fort  : .880  ” and  water. 
At  a rough  estimate  somewhere  about  four  fluid  drams 


THE  WAY  OF  SENSITISING 


37 


of  this  half -strength  solution  will  be  needed  to 
neutralise  a forty-ounce  bichromate  bath. 

To  sensitise  the  gravure  tissue,  cut  up  as  many  pieces 
as  you  want  to  a size  which  will  allow  of  them  going 
comfortably  on  their  squeegeeing  plates.  Go  into  the 
dark  room  and  switch  on  the  brightest  yellow-screened 
light  you  have  got.  Fill  a suitable -sized  dish  with  the 


Fig.  13. — Copper  plate  tools.  (Back)  Old  type  double-ended  tool  : 
Etching  needle  one  end  and  blunt-nosed  burnisher  the  other. 
(Middle)  New  pattern  Kimber  large  straight  burnisher.  (Front) 
Kimber  thin  curved  burnisher  (my  favourite  shape). 

sensitiser,  plunge  a piece  of  tissue  in  it,  turning  sides 
and  removing  air  bubbles  rapidly.  In  from  one  to 
three  minutes,  according  to  temperature,  the  tissue  will 
be  flat  and  limp  but  not  quite  flaccid  to  the  point  of 
sliminess.  At  this  point  get  it  down  on  the  drying  plate 
and  squeegee  well  into  contact  with  a flat  squeegee. 
One  way  of  avoiding  air  bubbles  is  to  slip  the  surfacing 
plate  or  glass  into  the  sensitising  dish  underneath  the 
tissue  and  lift  the  two  out  together  in  contact,  draining 
excess  solution  back  into  the  dish. 

Did  I mention  the  correct  preparation  of  the 
squeegeeing  plate’s  surface  to  ensure  tissue  stripping 


38 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


off  again  when  dry  without  trouble  ? It  is  the  usual  : — 
French  chalk  wetted  with  a little  methylated  spirit, 
rubbed  well  over  the  plate  with  a clean  linen  rag  and 
thoroughly  polished  off  again. 

Next  the  tissue  must  dry  thoroughly,  evenly,  and  in 
a definite  period  of  time.  It  must  either  strip  itself 

or  be  ready  for  stripping 
in  not  less  than  twTo,  nor 
more  than  four,  hours. 
To  do  that  a simple  way 
is  to  play  a steady  cur- 
rent of  cool  air  from  the 
electric  fan  upon  the 
back  of  the  squeegeed 
tissue  for  two  hours  to 
three  hours,  then,  and 
not  before  then,  start- 
ing up  the  radiator  and 
standing  it  in  such  a 
position  that  the  fan 
will  blow  warm  air  from  it  evenly  on  to  the  squeegee 
plate.  The  air  must  be  no  more  than  warm.  If  so  hot  as 
to  cause  tissue  to  snap  off  the  surfacing  plate  within 
half  an  hour  the  position  of  the  radiator  is  too  close. 
Minute  attention  to  such  detail  matters  as  the  above  is 
of  great  importance  for  success  in  photogravure. 

When  the  tissue  is  stripped  from  the  drying  plates 
examine  its  surface  under  yellow  screened  light,  looking 
for  any  minute  imperfections  such  as  traces  of  air-bells, 
particles  of  dust,  and  so  forth.  Mark  the  position  of 
each  on  the  back  of  the  tissue  with  a black  chalk  pencil 
and  cut  up  for  printing  in  such  a way  as  to  throw  out  the 
blemished  portions  (fig.  14), 


Fig.  14 — Conventional  marking  of 
back  of  sensitised  tissue  to  indicate 
surface  blemish. 


STORAGE  OF  SENSITISED  TISSUE 


39 


Unless  tissue  is  to  be  printed  from  within  thirty-six 
hours  I most  strongly  advise  storage  in  a calcium 
storage  case.  Even  with  such  storage  I consider  ten 
days  the  outside  safe  keeping  time  of  gravure  tissue 
after  sensitising. 


CHAPTER  VI 


Screening  and  printing  gravure  tissue.  Suitable  and 
unsuitable  light.  Mottling  and  the  way  to  avoid  it. 
Suitability  of  sunlight.  Preparing  copper  for  the 
tissue.  Getting  tissue  on  to  the  copper. 

Our  tissue  being  sensitised  and  trimmed  to  a size 
rather  larger  than  the  size  of  the  transparency  and  a 
trifle  less  than  that  of  the  copper  plate  upon  which  it 
is  to  be  put  down  we  are  ready  to  print  it.  I have 
explained  that  in  screen  photogravure  the  tissue  has 
to  be  printed  twice  over,  the  first  time  being  called 
“ screening.”  This  screening  may  be  either  to  direct 
sunlight,  to  the  direct  rays  from  the  unobscured  crater 
of  an  arc  lamp,  or  (as  I have  found)  to  approximately 
parallelised  rays  from  a collimating  lens  set  before  an 
incandescent  high-power  lamp  of  the  kind  known  as 
a gas -filled  focus  lamp.  Focus  lamps  differ  from  the 
ordinary  street -lighting  type  of  gas -filled  high -power 
lamp  in  that  their  filament  coils  are  arranged  as  closely 
together  as  possible,  so  as  to  bring  the  light-source 
more  nearly  to  a “ point.”  Generally  the  coils  are  set 
in  the  shape  of  a flat  grid,  which  enables  most  of  the 
light  from  them  to  be  approximately  parallelised  by 
mounting  in  front  of  the  lamp  a single  bi-convex 
condenser  lens.  It  should  have  a diameter  at  least 
equal  to  the  diagonal  of  the  largest  sized  transparency 
to  be  printed  from. 


CAUSES  OF  MOTTLING 


41 


Diffused  lighting  of  any  kind,  and  no  matter  how 
bright,  is  absolutely  unsuitable  for  screening  photo- 
gravure tissue.  We  had  better  understand  why,  and 
so  save  ourselves  from  delay  and  tissue  waste  later  on. 
The  reason  is  that  the  diameter  of  the  actual  lines 
printed  on  the  tissue  from  the  screen  being  no  greater 
than  approximately  one  four-hundredth -and-hftieth 
part  of  an  inch,  the  slightest  creeping  of  light  round 
them  or  between  them  causes  their  form  to  be  lost. 
Also  we  must  understand  that  in  practice  no  amount 
of  pressure  will  bring  screen  and  tissue  absolutely  into 
contact  at  all  points.  That  being  so,  the  one  way  of 
ensuring  a clean-cut  and  perfect  screen  printing  is  to 
use  bright  direct  light  and  rely  upon  the  screen’s  cast 
shadow  printing  cleanly  even  where  there  is  slight 
failure  of  contact.  Printing  to  diffused  light  gives 
rise  to  a series  of  humpy  alternations  of  alternate 
running  together  of  the  screen  lines  and  entire  failure 
to  record  them.  In  the  resist  these  markings  develop 
and  etch  as  a mildew-like  mottle,  especially  and 
ruinously  obtrusive  in  high-light  details  of  the  picture. 
Its  appropriate  name  of  “ mottling  ” stands  as  a dread 
word  to  the  photogravure  plate  maker,  though, 
curiously  enough,  quite  a number  of  hrst-class  workers 
do  not  seem  to  understand  the  true  cause  of  it,  but 
tell  you  vaguely,  “ You  can’t  use  anything  else  except 
a single  actinic  arc  lamp  for  screening  the  tissue,  or 
mottling  will  result.” 

As  a matter  of  fact,  there  is  another  kind  of  mottling, 
due  to  heating  of  the  screen  and  tissue  behind  it 
when  the  screen  light  is  over-hot  or  over-close  to  the 
printing  frame.  Heat  mottle  markings  come  through 
steam  baked  out  of  a not  perfectly  dry  tissue.  The 

D 


42 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


two  preventives  of  it  are  storage  of  tissue  in  calcium 
cases,  and  taking  means  (which  I shall  shortly  describe) 
to  keep  the  screening  light  cool. 

Meanwhile  let  us  deal  first  with  the  simplest  of  all 
screening  methods  where  the  simplest  of  all  lights  is 
available.  For  this  the  screen  is  laid  in  the  pressure 
or  vacuum  frame,  carefully  dusted,  tissue  is  laid  upon 
it,  also  carefully  dusted,  the  frame  closed,  pressure 
put  on,  and  the  loaded  frame  taken  out  into  bright 
sunlight.  Here  it  must  be  stood  down  squarely 
facing  the  sun  and  left  to  print,  the  Sawyer  actino- 
meter  being  stood  by  the  side  and  printing  being 
carried  until  the  actinometer  shows  two  full  tints. 
That  is  to  say,  the  ground  round  about  the  figure  2 
printed  out  on  the  albumenised  paper  must  at  least 
match  the  shade  of  the  test  strip  edging.  Personally, 
I like  to  take  screening  on  to  nearly  three  tints.  With 
a good  quality  screen  the  extra  time  does  no  harm. 
Afterwards,  at  once  return  the  frame  to  the  yellow-lit 
room,  remove  the  screened  tissue  from  the  screening 
frame,  and  place  it  behind  the  prepared  transparency 
in  an  ordinary  printing  frame. 

This  time,  if  the  photogravure  plate  is  to  have  its 
etched  part  evenly  and  squarely  set  on  the  copper,  it 
is  necessary  to  see  that  the  tissue  is  so  laid  in  the 
frame  that  at  least  one  edge  is  parallel  with  the  corre- 
sponding edge  of  the  transparency  being  printed  on 
it.  There  is  no  difficulty  over  that,  for  the  tissue,  if 
of  sufficient  size,  will  overlap  the  positive  picture  all 
round,  its  edges  being  clearly  seen  through  the  clear 
glass  rim.  Having  got  an  edge  of  the  transparency 
picture  and  an  edge  of  the  tissue  parallel,  turn  the 
printing  frame  over,  and  holding  the  tissue  steadily 


PRINTING  FROM  TRANSPARENCY 


43 


in  place,  mark  upon  it  with  the  chalk  pencil  a mark 
indicating  which  boundary  has  been  selected.  I also 
mark  near  the  upper  edge  of  the  print  (to  be)  a T, 
denoting  “ top,”  (fig.  15).  The  frame  may  now  be 
closed  and  the  second  printing  (transparency  printing) 
done  to  diffused  light.  The  most  rapid  diffused  light 
I know  is  sunlight,  with  the  printing  frame  covered 
with  a.  thickness  or  two  of  ground  glass.  Arrange  a 
simple  frame  or  stand  to  hold  a good-sized  ground- 
glass  sheet,  and  place  this  a little  in  front  of  the  frame 
between  it  and  the  light.  Ojtce  again  we  judge  print- 
ing time  by  the  same  actinometer  as  before,  exposing 
it,  like  the  printing  frame,  to  sunlight  behind  the 
ground  glass,  or  to  simple  diffused  daylight.  This 
time  we  give  an  exposure  of  not  less  than  three  tints, 
though  in  some  of  my  work  I have  found  etching  go 
better  when  the  picture  printing  had  been  taken  to 
four  or  even  five  tints. 

Possibly  it  will  strike  you  that  in  what  I have 
written  about  screening  and  printing  photogravure 
tissue  there  has  been  little  call  for  the  exercise  of 
individual  discretion.  This  is  true,  and  is  due  partly 
to  exposure  latitude  of  the  tissue  both  in  screening 
and  transparency  printing  being  great.  The  real  call, 
and  a very  severe  call,  upon  individual  judgment  will 
come  only  with  actual  etching  of  the  copper.  When 
that  time  arrives  there  will  be  plenty  to  induce  con- 
centration of  mind. 

We  next  turn  to  the  preparation  of  the  copper  plate 
for  its  resist.  Copper  plates  are,  or  should  be,  supplied 
each  in  a separate  paper  wrapping  to  protect  the  surface 
from  scratches.  Take  the  plate  out,  holding  it  by  the 
edge  as  though  it  were  a wet  gelatine  plate,  for  it  is 


44 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


important  to  make  a habit  of  keeping  one’s  fingers  off 
it.  Hold  the  plate  in  a good  light,  and  examine  its 
surface  minutely.  If  small  scratches  are  seen  they 
should  be  rubbed  out  gently  with  the  burnisher 
moistened  with  a little  water  and  applied  almost 
flat-on,  with  a gentle  and  slow  backward  and  forward 
motion.  Hard  or  rapid  use  of  the  burnisher  heats 
the  copper  at  the  point  of  contact,  and  may  cause 
more  scratches  instead  of  removing  the  old  ones. 
Decide  whether  the  surface  of  the  plate  is  so  discoloured 
by  tarnish  as  to  be  the  better  for  a chemical  cleaning 
bath.  I always  omit  chemical  cleaning  where  possible. 
If  it  is  needed,  a suitable  bath  will  contain  half  a 
dram  each  of  pure  chromic  acid  and  strong  sulphuric 
acid  in  a pint  of  water.  Lay  the  copper  plate  in  an 
enamelled  or  china  dish  and  pour  on  the  tarnish  - 
remover  as  if  flooding  a negative  with  developer. 
The  effect  is  very  rapid,  and  the  plate  should  not  be 
left  in  the  bath  any  longer  than  necessary  to  change 
its  brown-black  shiny  surface  into  a light  brick-red 
one.  As  the  bath  gets  used  up  it  becomes  green  in 
colour.  It  should  be  thrown  away,  and  a fresh  one 
made  up,  at  about  the  yellow-green  stage.  Up  to 
that  point  it  can  be  used  over  and  over  again. 

The  next  thing,  after  getting  the  tarnish,  or  most 
of  it,  removed,  is  to  burnish  the  plate  with  the  willow 
charcoal  block.  Rinse  the  copper  well  under  the  tap, 
also  hold  the  charcoal  under  the  tap  for  a moment  to 
wet  the  end  of  it,  and  apply  the  end  of  the  block  to 
the  copper,  using  the  cross-grain  of  the  charcoal  as  a 
polishing  surface.  Work  the  charcoal  over  the  metal 
with  brisk,  smooth,  circular  motion  until  the  whole  of 
the  matt  appearance  left  by  the  tarnish -removing 


45 


CLEANING  COPPER  FOR  RESIST 

bath  is  gone  and  the  plate  takes  much  the  same  mottled 
shininess  as  though  the  copper  had  been  gently  beaten 
to  a polish  with  a hammer. 

The  third  cleaning  operation  is  to  place  a pinch  of 
whiting  in  a saucer,  or  in  a quarter-plate  dish,  moisten 
it  with  a few  drops  of  the  half-strength  stock  ammonia 
solution,  which  we  shall  bear  in  mind  we  have  already 
made  up  for  ourselves,  dip  the  hairs  of  a strong,  cheap 
nailbrush  in  the  whiting-ammonia  paste,  and  proceed 
to  scrub  the  plate  vigorously  all  over,  first  across  and 
across,  then  in  circular  sweeps  of  the  brush.  The 
ammonia  attacks  the  copper  slightly,  but  the  whiting 
cleans  the  surface  again  just  as  quickly,  so  that  pro- 
vided the  work  is  gone  at  with  good  speed  and  the 
plate  is  rinsed  under  the  tap  copiously  as  soon  as  ever 
the  brush  is  taken  off  it,  we  shall  in  this  way  get  a 
bright  even  copper  surface,  so  free  from  all  trace  of 
grease  that  the  tap  water  will  flow  over  it  without  a 
sign  of  formation  of  droplets. 

In  the  event  of  any  readers  being  familiar  with  the 
routine  of  plate  preparation  for  other  photo-mechanical 
processes  I will  add  that  this  bright  metal  surface  is 
the  only  one  I have  found  suitable  for  laying  down  the 
photogravure  resist  upon.  A nice  “ tooth  ” which 
one  might  think  to  be  more  calculated  to  hold  the 
resist  firmly  down,  really  defeats  its  object  by  permit- 
ting the  etching  fluid  to  undercut  the  gelatine  at  an  early 
stage  of  the  etching,  the  result  being  that  our  unhappy 
experimenter  finds  at  the  end  of  his  trouble  he  has  not 
really  succeeded  in  creating  any  printing  image  at  all. 

Cleaned  copper  plates  can  be  left  under  the  running 
tap  or  covered  with  plain  water  in  a dish  while  printed 
tissue  is  soaked  and  made  ready  for  them  The 


46 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


waiting  interval  will  not  be  more  than  two  or  three 
minutes. 

Up  to  now  I have  not  touched  upon  one  fault  some- 
times found  in  copper  plates  as  they  are  sent  out  by 
the  dealer.  This  is  the  presence  in  them  of  quite  deep 
but  small  pits.  Personally  I have  never  made  the 
attempt  to  correct  these,  though  it  can  be  done  by  a 


Eig.  15. — Tissue  showing  back  with  code  markings  denoting  plate  top 
“ T ” and  side  to  be  squeeged  parallel  wdth  plate  edge  “ I.” 

skilled  copper  plate  worker.  My  mode  of  dodging  the 
difficulty  is  to  reject  the  plate  or  to  cut  it  up  into 
smaller  ones  in  such  a way  as  to  throw  out  the  pitted 
portion.  The  regular  way  to  deal  with  a pit  is  the 
following  : First  of  all,  by  means  of  a pair  of  callipers, 
find  and  mark  the  exact  position  of  the  surface 
blemish  relatively  to  the  plate’s  back.  The  plate  must 
then  be  laid  face  downward  upon  a flat,  polished  steel 
anvil,  a flat-nosed  punch  must  be  centred  on  the 


ADVANTAGE  OP  INDUSTRIAL  “METH.” 


47 


marked  spot,  and  some  sharp  blows  given  upon  the 
punch  with  a light  hammer.  If  rightly  done,  these 
hammer-blows  will  turn  the  pit  into  a bump  on  the 
face  of  the  plate.  The  bump  has  to  be  levelled  by 
scraping  down  with  a copper  plate  scraping  tool,  used 
much  the  same  as  a motor  mechanic  used  the  scraper 
wherewith  he  faces  bearings  of  engine  shafts.  It  is  a 
ticklish  job,  requiring  skill  and  practice.  Finally,  the 
scraped  portion  of  the  plate  is  evened  up  by  polishing 
first  with  powdered  pumice  and  water,  then  with 
jewellers5  rouge,  and  finally  with  willow  charcoal  and 
whiting-ammonia,  as  already  described. 

We  are  ready  to  soak  the  printed  tissue  for  transfer. 
The  soaking  solution  consists  of  three-quarters  water 
and  one-quarter  methylated  spirit.  If  it  is  possible 
to  get  hold  of  industrial  spirit,  this  should  be  used. 
It  can  be  bought  from  the  Methylating  Co.,  Ltd., 
Kinnaird  House,  Pall  Mall  East,  London,  S.W.  1,  but 
only  by  persons  holding  a permit  to  buy.  The  permit 
has  to  be  applied  for  to  the  local  Supervisors  of  Customs 
and  Excise,  who  will  require  to  know  the  purpose  for 
which  the  spirit  is  to  be  used  and  to  be  satisfied  that 
it  will  not  be  mixed  into  any  drug  or  compound 
intended  to  be  sold  for  internal  administration. 

Those  who  prefer  to  make  shift  with  ordinary 
methylated  spirit  (as  I did  at  first)  should  try  samples 
from  different  sources  until  a suitable  one  has  been 
hit  upon.  Ordinary  spirit,  having  paraffin  and  resin- 
ous matter  dissolved  in  it,  goes  cloudy  on  mixing  with 
water  (which  does  not  greatly  matter),  but  after 
standing  a little  there  arises  a solid  scum  which  can 
be  got  rid  of  by  filtering  the  mixture  through  chamois 
leather. 


48 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


Tissue  must  be  placed  in  the  weak  spirit  and  water, 
air  bubbles  being  rapidly  removed  from  back  and 
front  of  it  with  a camel-hair  mop  brush  or  a piece  of 
clean  linen  rag.  Immersion  time  usually  is  between 
one  and  two  minutes.  The  tissue  must  be  allowed  to 
absorb  enough  of  the  mixture  to  flatten  out  and 
become  moderately  limp,  but  not  at  all  slimily  flaccid. 
At  this  point  take  the  newly  cleaned  copper  plate, 
place  it  in  the  tissue  soaking  dish,  run  the  tissue  over 
it,  face  to  face,  and  manoeuvre  it  into  its  right  position. 
Here  comes  in  the  use  of  the  black  chalk  markings  on 
the  tissue  back.  From  them  you  know  which  is  the 
top  and  which  the  bottom  of  the  picture  ; also  which 
edge  of  the  tissue  must  be  placed  strictly  parallel 
with  its  equivalent  edge  of  the  plate  in  order  to  ensure 
that  the  resist  shall  transfer  squarely  upon  its  copper 
basis.  Having  got  the  tissue  rightly  placed,  pass  your 
hand  firmly  over  it,  and  it  will  stick  upon  the  copper 
tightly  enough  to  allow  of  the  two  being  withdrawn 
from  the  soaking  solution  without  shifting  their 
relative  positions.  Lay  the  plate  upon  the  bench  top 
and  squeegee  out  excess  of  solution  with  the  flat 
squeegee.  General  practice  at  this  point  is  the  same 
as  in  ordinary  carbon  printing,  or  in  “ Carbro.”  Mop 
any  remaining  water-drops  off  the  back  of  the  tissue 
and  stand  the  copper  plate  on  edge  for  sufficient  time 
fco  allow  of  the  adhering  tissue  becoming  practically 
dry  to  the  touch.  This  will  not  take  less  than  half 
an  hour  and  should  not  take  more  than  an  hour  and  a 
half.  My  usual  way  is  to  let  the  plate  stand  for  about 
an  hour,  then,  if  necessary,  to  play  the  breeze  from 
the  electric  fan  upon  it  for  five  or  ten  minutes  as  a 
finisher.  On  no  account  turn  on  artificial  heat  at  this 


SAFE  LTGHTTNTG  FOR  SENSITIVE  TISSUE 


49 


point,  and  do  not  attempt  to  get  the  back  of  the  tissue 
hand-dry  in  a hurry,  or  the  resist  will  show  it  later  on. 
As  before,  I favour  bright  yellow  or  orange  light  for 
the  soaking  and  setting  of  the  tissue  on  the  copper, 
and  total  darkness  or  similarly  screened  non-actinic 
light  during  the  time  of  partial  drying.  The  reason  is 
that  bichromate -sensitised  gelatine  is  slightly  sensitive 
to  the  actinic  rays  in  ordinary * unscreened  artificial 
light  such  as  comes  from  modern  metal  filament 
electric  lamps.  Progress  of  etching  is  so  responsive 
to  every  microscopic  difference  of  thickness  of  the 
gelatine  resist  that  the  risk  of  even  slightly  altering 
this  by  carelessness  with  the  work-room  light  should 
be  avoided. 


CHAPTER  VII 


Describes  a novel , inexpensive  and  reliable  way  of  using 
incandescent  electric  light  for  screening  and  printing 
gravure  tissue.  The  system  is  applicable  to  alter- 
nating as  well  as  to  direct  current  supply  at  any 
town-lighting  voltage. 

Screening  and  transparency  printing  directions  so 
far  given  have  been  for  the  benefit  of  those  who  live 
in  sunny  enough  lands,  or  who  start  their  photogravure 
experiments  in  a sunny  enough  season,  to  be  able  to 
work  in  natural  light  with  reasonable  regularity.  If 
I left  things  at  this  point  we  wretched  dwellers  in  the 
Isles  of  Mist  should  not  get  very  far.  As  you  know 
I have  rigged  up  a simple  accessory  whereby  our 
screening  and  printing  may  be  both  cheaply  and 
certainly  done  in  any  studio  or  room  where  there  is  a 
supply  of  electric  energy,  the  light -source  T am  using 
being  a gas -filled  focus  lamp. 

My  present  one  is  a G.E.C.  tubular  focus  lamp  con- 
suming 1,500  watts,  having  a close-coiled  grid  filament 
of  tungsten  wire  and  giving  a nearly  white  light  of 
approximately  five  thousand  candle  power.  To  get 
this  brilliance  of  light  I over-run  the  lamp  by  10  per 
cent.  This  means  that  if  your  current  supply  is 
110  volts  you  order  a 100-volt  lamp  to  run  on  it.  If  it 
is  220  volts  you  use  a 200-volt  lamp.  On  a 240-volt 
circuit  (as  mine  is)  10  per  cent,  overrunning  is  arrived 

50 


SMALL  ARTIFICIAL  SCREENING  LIGHT 


51 


at  nearly  enough  by  using  a 220-volt  lamp.  Average 
life  of  lamps  overrun  to  this  extent  should  be  not  less 
than  400  to  500  burning  hours.  Greater  and  whiter 
light  still  can  be  got  by  overrunning  lamps  even  more, 
but  the  practice  is  uneconomic,  for  their  burning  life 
becomes  so  short  and  doubtful  as  to  be  ruinous  in 
renewal  expenses. 


% 


Fig.  16.— Lamp  and  collimator  arranged  for  screening  by 
artificial  light. 

My  1,500  watt  focus  lamp  fits  in  a “ giant  55  Edison 
screw  holder  which  is  attached  to  the  arm  of  a “ Eocus- 
lite  ” lamp  tray.  Thus  the  lamp  burns  like  a great 
candle  and  can  be  swivelled  and  raised  and  lowered 
on  the  tray  for  optical  centring  behind  the  single 
plano-convex  lens,  which  acts  as  collimator  (fig.  16). 
My  lens  is  an  eight  and  a half  inch  diameter  one,  form- 
ing one  glass  of  an  old  enlarger  condenser.  By  setting 
the  interval  between  collimating  lens  and  light-source 


52 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


correctly  the  hght-beam  from  the  condenser  can  be 
made  almost  parallel.  Actually  I allow  the  beam  to 
err  if  anything  on  the  slightly  divergent  side,  for  that 
gives  me  a light-spot  which  at  two  feet  before  the 
condenser  lens  is  just  right  for  screening  and  printing 
tissue  large  enough  for  8J  in.  by  6 in.  plates.  Lamp 


Fig.  17. — screening  in  progress.  The  vacuum  frame  is  slightly 
turned  to  show  the  light  beam  striking  face  of  the  copy  screen. 


and  condenser  are  so  built  up  in  relation  to  each  other 
and  to  the  screening  table  top  that  when  the  vacuum 
frame  is  stood  vertically  in  its  appointed — and  duly 
marked  out — position,  the  approximately  parallelised 
light -beam  shall  strike  on  the  screen  fully,  and  always 
in  the  same  place  (fig.  17).  That  makes  it  a simple 
matter  to  lay  the  tissue  in  the  frame  so  that  it  all  gets 
screened  with  even  intensity. 

My  artificial  light-screening  arrangement  is  com- 


SCREENING  LIGHT  FURTHER  DESCRIBED 


53 


pleted  by  fixing  a bracket  or  platform  for  a fan  motor 
in  such  a position  that  all  the  while  screening  is  in 
progress  a brisk  breeze  of  cool  air  is  blown  upon  the 
frame’s  glass  to  keep  it  and  the  screen  and  tissue 
behind  it  from  ever  becoming  more  than  mildly  warm 
to  the  hand  (fig.  18).  There  is  the  whole  very  simple 
and  quite  effective  arrangement. 


Fig.  18. — View  of  incandescent  screening  and  printing  arrangement, 
showing  disposition  of  fan  for  cooling  the  light  beam. 


Those  portraitists  who  have  actinic  arcs  at  their 
command  can  use  them  just  as  they  are  as  screening 
lights.  They  should  select  one  lamp  only,  and  this  a 
single  crater  lamp,  for  each  screening  unit,  placing  it 
from  three  to  five  feet  away  from  the  frame  front, 
according  to  crater  intensity.  If  possible  it  will  be 
well  to  arrange  a breeze  fan  to  play  upon  the  glass  of 
the  frame,  as  already  described  for  the  focus  lamp 
arrangement. 


54 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


With  the  focus  lamp  and  condenser  screening 
accessory,  or  with  a good  even-burning  actinic  arc, 
neither  screening  time  nor  transparency  printing  time 
need  checking  by  the  actinometer  after  the  first  once 
or  twice.  A worker  will,  by  then,  come  to  know  what 
timing  corresponds  with  two,  three,  four,  or  five  tints. 
Henceforward  his  watch,  or  a timing  clock,  will  do  the 
rest.  As  a guide,  I find  that  for  two  full  tints  with 
the  overrun  1,500  watt  focus  lamp  and  eight  and  a half 
inch  condenser,  set  as  described  above,  screening  time 
is  seven  minutes.  For  transparency  printing  to  the 
same  light-source,  but  with  a sheet  of  ground  glass 
interposed  between  it  and  the  printing  frame,  timing 
for  three  and  a half  tints  is  just  fifteen  minutes. 
When  printing  to  arc  light,  the  second  exposure  (that 
behind  the  transparency)  should  also  be  done  with 
ground  glass  as  a diffuser  before  the  printing  frame. 

At  the  risk  of  wearying  the  reader  I ask  him  to 
bear  in  mind  (it  has  already  been  explained  in  a former 
part  of  these  directions)  why  screening  must  be  to 
direct,  undiffused  light.  The  reason  why  diffused  light 
is  correct  for  the  second  printing  is  the  same  as  why 
we  prefer  it  when  doing  any  other  kind  of  photographic 
printing.  It  does  not  so  searchingly  reveal  minor 
blemishes  in  the  texture  of  the  printing  transparency, 
such  as  minute  dust  motes  impaled  in  the  varnish,  or 
individual  pencilling  of  the  retouching. 

Those  who  may  not  be  able  to  tap  a sufficiently 
heavy  lighting  supply  circuit  to  draw  from  it  fifteen 
hundred  watts,  can,  if  they  have  electric  fires  installed, 
make  an  arrangement  with  the  electric  supply  company 
by  which  they  may  be  permitted  to  plug  the  high 
power  lamp  off  the  heating  circuit.  Otherwise  they 


MORE  POINTS  ABOUT  SCREENING  LAMPS 


55 


must  be  content  with  a smaller  focus  lamp,  and  increase 
screening  and  printing  time  accordingly.  I have  used 
for  this  purpose  as  small  a lamp  as  one  of  400  watts. 
Such  a lamp  of  200  volts,  run  on  a 220  volt  circuit,  will 
take  very  little  over  two  amperes,  therefore  being 
capable  of  being  run  off  any  ordinary  house  lighting 
bracket  (through  a lamp  holder  plug  and  flex)  without 
fear  of  “ blowing  55  the  fuse  and  su  temporarily  throw- 
ing the  sub -circuit  out  of  use.  The  relatively  low 
candle  power  may  not  be  ideal  for  professional  work, 
but  an  amateur  or  experimenter  who  does  not  mind 
waiting  an  hour  and  a half  or  thereabout  for  the  total 
screening  and  transparency  printing  time  will  be  quite 
able  to  get  good  results  during  the  winter  when  the 
sunlight  has  deserted  us.  Miniature  arcs  consuming 
rather  under  five  amperes  are  also  possible  screening 
and  printing  units,  but  the  light  from  them  is  not  very 
constant  either  in  quantity  or  quality.  Where  they 
are  used,  timing  had  better  be  checked  always  by  the 
actinometer. 


CHAPTER  VIII 


Development  of  a photogravure  resist.  The  stages  by 
ivhich  it  is  evenly  dried.  How  to  judge  the  resist 
arid  decide  if  the  plate  is  good  enough  for  etching. 
Putting  on  its  acid-proof  border  and  backing. 

If  yon  are  well  accustomed  to  the  development  of 
carbon  prints  I would  still  suggest  that  you  do  not 
turn  up  your  nose  at  the  attempt  I am  going  to  make 
at  describing  my  way  of  developing  photogravure 
resists.  In  general  the  practice  is  the  same  as  with 
ordinary  carbon  work,  but  there  are  small  differences 
between  the  two  which  stand  between  success  and 
failure. 

The  first  one  of  these  the  carbon  worker  will  already 
have  come  up  against.  In  photogravure,  instead  of 
“ single  transfer  5 5 being  made  on  to  a surface  previously 
prepared  by  coating  with  a thin  layer  of  toughened 
gelatine,  and  instead  of  the  tissue  being  ready  for 
development  as  soon  as  it  has  had  a quarter  of  an 
hour’s  pressing  in  contact  with  the  transfer  support, 
we  have  to  put  our  tissue  down  upon  absolutely  bare 
copper  and  to  rely  for  its  adhesion  upon  letting  it  dry 
to  the  point  where  it  sticks.  If  you  start  develop- 
ment before  then  the  image  on  the  copper  will  frill, 
or  bodily  float  away,  and  be  ruined. 

However,  our  tissue  is,  we  will  suppose,  dry  enough 
by  now,  which  means  almost,  but  not  quite,  dry.  If 

56 


TEMPERATURE  OF  RESIST  DEVELOPMENT 


57 


so,  it  is  ready  for  immersion  in  water  at  ] 10  to  115  Fahr. 
Text -books  and  printed  instructions  tell  us  to  start  with 
the  water  at  105  Fahr.  and  raise  the  temperature 
gradually  to  115  Fahr.  I have  found  the  lower 
temperature  time-wasting,  and  if  there  are  two  things 
to  be  avoided  in  photogravure  resist  development 
they  are  waste  of  time  and  incomplete  washing  out 
of  the  unaltered  gelatine.  My  way  is  to  half -fill  an 
enamelled  iron  dish  with  warm  water,  and  to  keep  this 
water  at  115  exactly,  by  the  help  of  a small  electric 
boiling  stove  (or  gas  ring)  and  a chemical  or  dairy 
thermometer.  Dairy  thermometers,  also  known  as 
bath  thermometers,  are  much  cheaper  than  the  regular 
chemical  ones  and  are  sold  with  removable  wood 
covers  which  protect  them  from  breakage  when  out 
of  use. 

Put  the  copper  plate  in  the  hot  water,  and  at  once 
free  it  and  the  adhering  tissue  plaster  from  air  bubbles. 
This  is  easily  done  with  the  fingers,  or  with  a camel 
hair  mop  brush.  At  first  the  copper  will  withdraw  a 
good  deal  of  heat  from  the  bath  so  that  its  temperature 
will  drop,  and  we  must  apply  more  warmth  to  bring 
it  back  to  115  or  even  120  Fahr.  Generally  three  or 
four  minutes  elapse  before  slight  oozing  at  the  edges 
of  the  tissue  intimates  that  the  time  has  arrived  when 
the  paper  backing  can  be  stripped  off.  To  do  this  a 
needle  point  or  thin  knife  blade  has  to  be  very  care- 
fully and  lightly  inserted  between  tissue  and  paper 
back  at  one  corner  of  the  plate.  A slight  attempt  at 
upward  pulling  will  show  whether  the  paper  is  ready 
for  stripping.  If  not,  and  in  face  of  expert  instruction 
to  the  contrary,  I do  not  hesitate  to  raise  the  tempera- 
ture of  the  water  to  125  Fahr.,  and  in  the  last  event 


58 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


to  add  a very  little  ammonia  solution  to  it.  Do  not 
use  ammonia  as  a regular  practice.  It  ought  not  to 
be  necessary,  and  it  makes  subsequent  steps  of  our 
process  more  delicate.  As  soon  as  the  corner  of  the 
paper  backing  is  free,  double  it  on  itself  and  pull 
gently,  and  it  should  come  away.  But  strip  it  off 
slowly  and  with  circumspection,  never  losing  sight  of 
the  fact  that  the  bare  copper  has  nothing  like  the 
grip  of  prepared  transfer  paper,  so  that  to  get  the 
paper  away  without  any  hint  of  frilling  is,  if  not  a real 
test  of  skill,  at  least  a sign  of  previous  practice. 
Keep  developing  temperature  down  to  120  Fahr.  if 
possible,  125  Fahr.  is  the  absolute  limit  of  safety. 

Development  is  exactly  as  for  carbon,  and  should 
preferably  be  done  by  generous  laving  with  the  hot 
water.  Some  workers  finish  up  by  very  gentle  appli- 
cation of  a camel  hair  brush  or  of  a tuft  of  absorbent- 
cotton  wool  to  make  sure  the  last  of  the  free  pigment 
and  soluble  gelatine  has  been  got  rid  of.  I have  tried 
it,  and  cannot  deny  that  etching  gets  a rather  better 
move  on  in  the  early  baths  when  it  is  done,  but  believe 
the  general  gradation  scale  of  the  finished  plate  suffers. 
Anyway,  lave  quite  hard  at  the  finish  and  keep  it  up 
for  at  least  a minute  after  the  image  seems  to  be  fully 
out. 

What  will  our  plate  look  like  at  this  stage  ? Quite 
probably  inspection  of  the  image  will  lead  us  to 
believe  wTe  have  got  under-exposure.  Anyway,  take 
the  developed  plate  out  of  the  hot  water,  stand  on 
end  to  drain  for  not  more  than  two  minutes,  until  the 
copper  is  just  warm,  then  rinse  with  cold,  or  in  winter 
with  almost  cold  water,  drain  again  for  not  more  than 
another  two  minutes  and  plunge  into  a bath  of  half 


NECESSITY  OF  EVEN  DRYING 


59 


and  half  methylated  spirit  and  water.  Rock  evenly 
in  this  bath  for  one  minute  or  a minute  and  a half. 
Meanwhile  take  a clean  dry  chamois  leather  and  moisten 
it  in  spirit  and  water  mixture  of  exactly  the  same 
strength  as  the  resist  is  soaking  in.  That  is  of  vital 
importance.  Pick  out  the  plate,  drain  on  end  for 
one  minute,  wring  out  the  chamois  leather,  roll  it 
into  a tight  pad  and  rock  the  pad  gently  over  the 
surface  of  the  resist.  This  is  frankly  a time  when 
the  beginner  will  have  cause  to  hold  his  breath.  Any 
friction  between  leather  and  resist  caused  by  falling 
into  a wiping  instead  of  a simple  rocking  action  will 
probably  rip  and  spoil  the  resist  image.  On  the  other 
hand  the  developed  tissue  has  to  be  rapidly  “ blotted  ” 
with  the  chamois  leather  till  all  surface  moisture 
has  been  completely  and  evenly  removed.  Wherever 
drops  or  wet  patches  are  allowed  to  remain,  there  the 
etching  solution  will  bite  unevenly  and  the  plate  will 
take  to  itself  a crepe -like  water  mark  in  the  final 
etching  baths.  Success  at  this  point  of  the  operations 
depends  upon  sheer  manipulative  skill.  As  soon  as 
the  plate  is  completely  surface -blotted  it  should  be 
stood  on  end  and  a smart  current  of  air  (which  may  be 
warmed)  should  be  blown  upon  it  by  the  breeze  fan 
until  the  resist  is  dry.  Drying  time  ought  not  to  be 
more  than  ten  minutes  at  most,  and  it  is  essential 
that  all  parts  of  the  plate  representing  equal  density 
should  dry  simultaneously.  A plate  left  to  dry  slowly 
and  progressively  will  etch  with  graduated  density 
from  end  to  end  as  the  result. 

Now  to  examine  the  dry  resist.  First  of  all,  apart 
from  any  question  of  pictorial  image,  the  whole  surface 
when  viewed  under  a magnifying  lens,  should  show  its 


60 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


screen  ruling  as  a clean-cut  hatching  of  pigmented 
gelatine  cross-lines.  Next,  to  judge  of  the  image,  the 
plate  should  be  held  at  an  angle  to  a good  light  so  that 
the  sheen  from  the  underlying  copper  surface  gleams 
brightly  in  the  parts  representing  shadow  and  deeper 
half -shadow  tones.  Almost  everywhere  faint  shadow 
details  should  then  be  just  discernible  as  pigmented 
clouding  of  the  full  brightness  of  the  metal.  From 
this  the  density  scale  should  ascend  till  high-light  tones 
are  covered  with  a thickness  of  pigment  only  a trifle 
less  pronounced  than  the  pigment  -covering  of  the 
picture  border  itself. 

We  proceed  to  a second  general  examination  for 
blemishes.  Mottling,  if  present,  will  show  as  small 
glossy  pigmented  areas  which  cannot  be  accounted  for 
by  reference  to  the  printing  transparency.  Uneven 
drying  marks  also  show  glossy,  but  more  or  less  as 
streaks,  like  the  patches  seen  upon  smooth  streams  in 
summer  time.  A different  kind  of  blemish  which, 
unfortunately,  I find  sometimes  crops  up  upon  an 
otherwise  passable  resist,  is  a small  area  of  unduly 
thin  density  having  in  the  middle  of  it  a speck  of 
embedded  matter  foreign.  The  whole  defect  is  usually 
not  much  bigger  than  the  head  of  a large  pin,  and  can 
be  likened  to  the  “ pin-hole  ” encountered  in  our 
negatives  from  time  to  time.  Probably  the  cause  of 
the  trouble,  as  with  pin-holes  in  gelatino -bromide 
plates,  is  iron  rust.  Generally  so  small  a blemish  can 
be  touched  out  before  the  plate  goes  into  the  etching 
bath. 

Where  a spirit  and  water  bath  has  not  been  filtered 
previous  to  each  time  of  using,  and  sometimes  even 
when  it  has  been,  small  particles  of  fluffy  matter  will 


TOUCHING  TJP  THE  RESIST 


61 


be  caught  up  from  it  and  adhere  to  the  dry  resist 
surface.  These  may  often  be  detached  by  the  very 
gingerly  use  of  the  retouching  knife  in  the  hands  of  a 
fairly  skilful  worker,  but  the  resist  must  not  be  cut 
through  in  the  process.  If  they  are  left  alone  they 
tend  to  act  as  tiny  wicks  leading  the  etching  fluid  too 
rapidly  to  the  copper  immediately  below  them,  with 
the  result  that  a minute  dark  speck  appears  later  on  in 
the  printing  surface.  On  this  account  I take  care  to 
remove  adherent  fluffy  particles  from  high -lights  of 
the  plate,  but  do  not  worry  so  much  when  they  occur 
in  the  deeper  half-tones,  or  shadows. 

If  on  examination  the  resist  shows  clean  screening, 
a full  range  of  density  tones  from  (apparently)  bare 
copper  to  liberal  pigmentation,  and  no  surface  defects, 
the  plate  can  be  accepted  and  be  prepared  for  etching. 
If  it  shows  mottling  or  uneven  drying  marks  no 
attempt  should  be  rnacle  to  proceed  further,  but  the 
resist  should  be  re -wetted,  scrubbed  off  with  a clean 
nail  brush,  and  the  copper,  if  needed  immediately  for 
a further  attempt,  should  be  given  another  scrub  with 
whiting  and  ammonia,  as  previously  described.  It 
will  then  be  ready  again  for  squeegeeing  into  contact 
with  a new  screened  and  printed  tissue.  But  suppose 
the  resist  is,  generally  speaking,  even,  but  has  a pin-hole 
or  two,  or  some  similar  defect  occupying  no  large  area 
of  the  copper,  such  as  a minute  rift  in  the  resist  surface 
only  noticeable  under  the  magnifier  or  when  the  plate 
is  tilted  underneath  a lamp  till  the  bright  metal  gives 
a flash  ? What  then  ? 

Should  the  resist  be  scrapped  under  these  circum- 
stances ? Let  each  man  decide  for  himself,  but  I can 
say  this  : that  many  passable  printing  plates  of  my 


62 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


own  had  to  be  doctored  for  more  than  one  of  these 
minor  defects  before  they  went  to  the  etching  room. 
That  is  one  of  the  wonders  of  photogravure — the  simple 
way  in  which  the  dehcate  photographic  work  and  even 
quite  clumsy  hand  work  will  mingle  in  the  printing 
plate  to  one  harmonious  whole. 


Fig.  19. — Plate  etched  and  with  the  gravure  resist  removed,  but  the 
bitumen  resist  border  still  on,  and  the  exposed  metal  within  the 
border  as  yet  uncleaned.  Xote  that  it  looks  like  a failure. 

To  make  ready  the  plate  for  etching  not  only  must 
minute  blemishes  be  touched  out  with  acid  resist 
varnish  but  a coating  of  the  same  varnish  has  to  be 
applied  to  the  back  of  the  plate,  to  its  edge  and  to  the 
front  border.  Fig.  19  will  show  what  the  border 
appears  like.  My  own  practice  is  to  do  the  bordering 
first  of  all.  Remember,  the  tissue  prints  its  own 
border  of  etch-resisting  gelatine  and  so  all  that  is,  or 


REASON  FOR  RESIST  BORDERING 


63 


should  be,  necessary  is  to  paint  on  a rim  of  acid  resist 
varnish  which  will  overlap  this  gelatine -pigment 
border  and  continue  it  to  the  plate’s  edge.  Then,  if 
we  etch  the  plate  just  rightly,  we  shall  stop  short 
before  the  gelatine  bordering  has  been  penetrated  by 
the  etching  fluid  to  the  point  of  attacking  the  underlying 
metal. 

It  will  be  observed  there  is  a “ should  be  ” about 
that.  Anyway,  a more  certain  picture  bordering  can 
be  put  on  by  ruling  boundary  lines  about  the  edges  of 
the  resist  picture.  The  lines  should  preferably  miss 
the  picture  by  about  the  thirty -second  part  of  an 
inch.  In  that  way  the  original  photographically 
printed  picture  boundary  limits,  which  are  always 
best,  will  be  those  retained  on  the  plate,  but,  in  the 
event  of  slight  penetration  of  the  border  gelatine 
occurring,  the  faint  band  of  tint  so  produced  will  be 
too  narrow  to  be  noticeable. 

Rule  the  border  boundary  lines  with  a ruling  pen 
of  the  sort  supplied  by  mathematical  instrument 
makers  and  found  in  boxes  of  compasses.  An  ordinary 
pen  nib  will  not  do.  If  you  try  to  rule  with  it  on  the 
resist  the  lines  will  run. 

Acid  resist  varnish  is  made  by  dissolving  bitumen 
in  benzine  and  adding  enough  oil  of  lavender  to  prevent 
the  bitumen  coating  chipping  when  dry.  Or  preferably 
buy  thick  resist  varnish  ready  made.  It  costs  only 
about  half  a crown  a pint.  A coating  is  thick  enough 
to  prevent  action  of  the  etching  fluid  upon  the  under- 
lying metal  when  the  colour  of  the  copper  cannot  be 
seen  through  it.  Keep  a bottle  of  benzine  at  hand  and 
dilute  the  resist  varnish,  a little  at  a time,  till  it  is 
at  the  half -liquid,  half -viscid  consistency  which  just 


64 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


allows  of  it  flowing  from  the  pen  during  border  ruling. 
The  same  consistency  will  also  be  right  for  brush 
painting  the  edge  and  back  of  the  copper. 

If  you  keep  a sheet  of  glass  handy,  it  is  simple  to 
take  out  a little  of  the  jelly-like  concentrated  varnish 
upon  the  tip  of  a palette  knife,  add  a few  drops  of 
benzine,  work  up  the  whole  to  the  right  strength, 
and  with  it  charge  a small  camel-hair  brush.  The 
same  brush  will  do  for  filling  the  ruling  pen,  completing 
the  bordering  and  coating  the  edges  and  back  of  the 
plate.  The  back  can  conveniently  be  left  till  last  of  all. 

When  a plate  has  been  coated  and  the  varnish  is 
fairly  dry,  a little  application  of  warm  air  from  the 
radiator  and  breeze  fan  soon  gets  the  coating  hard 
enough  to  be  ready  for  the  etching  operations.  On  no 
account  heat  the  copper  really  hot  at  any  time  or 
the  expansion  of  the  metal,  occurring  coincidentally 
with  contraction  of  the  gelatine  resist  through  extreme 
desiccation,  will  probably  cause  the  resist  to  split 
off  the  copper  again,  just  as  a well  glazed  bromide 
jumps  off  its  glazing  plate  on  becoming  bone  dry. 
That  has  happened  to  me  a time  or  two,  and  occurring 
as  it  does  at  the  moment  of  thinking  you  are  ready  for 
the  etching  trough,  it  is  more  than  a little  irritating. 

As  to  touching  out  small  defects,  this  should  be 
done  with  a fine  sable  brush  dipped  in  a little  well- 
thinned  resist  varnish,  working  under  a reading  glass. 

One  more  use  for  acid  resist  varnish  at  this  stage  I 
have  discovered  for  myself,  though  I am  not  enough  of 
an  artist  to  be  able  to  take  advantage  of  what  I know. 
If  you  are  working  from  a transparency  wherein  the 
sky  is  uninteresting,  it  is  possible  to  add,  or  to  rein- 
force, clouds  by  painting  them  in  on  the  dry  resist 


RESIST  INSENSITIVE  TO  BENZINE 


65 


with  acid-proof  varnish  so  diluted  with  benzine  that 
it  is  no  more  than  a faint  brown  stain  upon  the  pig- 
mented gelatine.  Practice  alone  will  enable  a worker 
to  know  how  deep  a “ tint  ” painted  on  the  resist  in 
this  way  corresponds  with  how  great  lightening  of  the 
printing  tone  on  the  plate  eventually. 

Another  thing  can  be  said  here  for  the  comfort  of 
the  beginner.  Sensitive  as  the  resist  is  at  all  times  to 
traces  of  water,  you  may  apply  benzine,  or  even  pure 
spirit  of  turpentine,  to  the  gelatine  face  gently  with  a 
paint  brush,  or  even  on  linen  or  cotton  wool,  for  the 
purpose  of  removing  unwanted  varnish  marks,  and 
the  plate  will  afterwards  show  no  irregularity  of  etching 
on  this  account.  So  where  a mistake  is  made  with  the 
ruling  pen,  or  where  spotting  has  been  raggedly  done, 
it  is  merely  a question  of  taking  the  old  work  off  cleanly 
with  benzine  and  the  resist  can  be  re-ruled  or  re-spotted 
without  harm.  Now  to  etch  it.  Never  touch  the 
resist  with  your  fingers. 


CHAPTER  IX 


An  etching  bench  and  its  simple  arrangements.  Etching 
baths , their  graded  strengths  and  their  preparation. 
The  necessity  for  a clock  or  watch  and  also  for 
pencil  and  paper. 

When  we  come  to  the  etching  of  gravure  plates  we 
part  with  the  state  of  things  where  a simple  “ following 
the  book  of  words  ” will  see  us  through.  If  you  ask 
me  what  is  the  most  important  accessory  to  gravure 
etching  I say  without  hesitation  it  is  the  skill  that 
can  only  come  with  practice.  Any  man  who  etches  his 
first  plate  correctly  can  take  to  himself  no  credit  for 
doing  so.  His  success  will  only  be  a fluke.  He  has 
merely  put  off  the  evil  day.  We  all  have  to  learn. 

Take  seven  pounds  of  crystallised  ferric  chloride. 
They  call  it  crystallised  because  it  is  sold  in  shapeless 
lumps.  The  best  lumps  I have  come  across  are  supplied 
bv  Penrose.  They  are  quite  dry,  and  hold  so  little 
excess  of  acid  that  the  process  of  “ hydrating,”  about 
to  be  described,  is  comparatively  easy.  Place  the 
ferric  chloride  (otherwise  per  chloride  of  iron)  in  a china 
or  earthenware  bowl  (I  have  used  a borrowed  wash 
basin),  and  just  cover  it  with  boiling  water.  About 
two  to  three  pints  of  water  will  dissolve  the  whole  seven 
pounds,  if  it  is  poured  on  when  really  boiling.  When 
the  solution  has  cooled  down  somewhat,  but  before  it 
has  got  cold,  it  may  be  poured  into  a five-pint  Win- 

66 


PREPARING  AND  “ HYDRATING  ” ETCHING  BATH  67 

Chester  bottle,  which  it  should  just  about  fill.  Possibly, 
as  the  contents  of  the  bottle  become  quite  cold,  a certain 
amount  of  the  dissolved  perchloride  may  crystallise  out 
again.  It  does  not  matter.  The  saturated  solution, 
if  tested  with  the  Beaume  hydrometer,  will  be  found 
to  read  approximately  45  on  the  scale.  This  is  far 
above  etching  strength,  but  it  is  a very  convenient 
strength  for  the  stock  solution ' from  which  etching 
baths  are  made  up  by  dilution.  However,  before 
we  come  to  that  we  must  get  the  “ hydrating  ” done. 
The  term  signifies  a particular  routine  way  of  getting 
rid  of  the  last  traces  of  excess  of  acid  in  the  bath,  and, 
as  it  is  of  prime  importance  to  ourselves,  it  deserves  to 
be  well  understood. 

Ferric  chloride,  then,  as  we  may  have  surmised,  has 
the  property  of  attacking  and  dissolving  (“  etching  ”) 
copper,  and,  in  fact,  a good  many  other  metals  also. 
It  will  even  etch  iron  and  steel  more  or  less,  for  which 
reason. the  stipulation  was  made  that  solutions  of  it 
should  be  prepared  only  in  china  or  earthenware  vessels. 
Fierceness  of  its  attack  depends  upon  the  amount  of 
free  hydrochloric  acid  present,  and  because  the  attack, 
for  purposes  of  photogravure,  must  only  be  gentle,  and 
because  even  the  best  commercial  ferric  chloride  holds 
within  it  a certain  amount  of  free  acid,  this  acid  has  to 
be  completely  got  rid  of  before  we  can  use  the  etching 
fluid.  The  way  we  remove  it  is  by  stirring  into  the 
stock  solution  a sufficient  proportion  of  a sludge  of 
freshly  precipitated  ferric  hydrate  for  the  whole  of  the 
free  acid  to  combine  with  the  hydrate  and  form  with 
it  further  ferric  chloride.  Hydrating,  in  practice,  is 
simple  enough.  Pour  one  ounce  of  stock  perchloride 
solution  into  a chemical  measure,  dilute  it  with  ten 


68 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


ounces  of  water,  and  stir  in  enough  stock-ammonia  solu- 
tion from  our  half -strength  ammonia  bottle  to  precipi- 
tate the  hydrate  as  a brick-coloured  slime.  Allow  the 
measure  to  stand  for  an  hour  or  two  till  the  hydrate 
slime  has  settled  well  down,  tip  oh  the  liquid  from  the 
top  of  it,  stir  up  with  another  ten  ounces  of  clean 
water,  allow  to  settle  once  again,  and  this  time, 
after  throwing  away  the  wash  water,  pour  the  hydrate 
into  the  perchloride  stock  bottle  and  stir  well  up. 

Stirring  should  be  repeated  a few  times  at  intervals 
of  a day  or  two,  or  when  you  think  of  it,  and  if  a cloud 
of  unaltered  hydrate  precipitate  still  remains  to  settle 
in  the  bottom  of  the  stock  bottle  you  may  be  satisfied 
that  the  etching  solution  has  been  sufficiently  “ neutral- 
ised ” to  be  safe  for  use  when  at  the  right  dilution. 

Now  about  that  dilution,  and  the  Beaume  hydro- 
meter. Those  who  have  no  previous  acquaintance  with 
the  characteristics  of  ferric  chloride  as  an  etcher  will 
probably  find  it  hard  to  believe  that  within  wide  limits 
this  solution  works  faster  according  as  you  dilute  it 
down  weaker.  I remember,  when  I was  young  and 
cocksure,  making  experiments  with  the  Warnerke 
process,  which  also  depended  upon  using  gelatine  as  a 
resist  when  etching  copper  with  ferric  chloride.  On 
that  occasion  I failed  lamentably,  because  I could  not 
believe  the  instruction  to  strengthen  the  solution  for 
gentler  action  was  anything  but  a particularly  gross 
misprint.  I hope  enough  has  been  said  about  it  to 
leave  no  room  for  any  reader  going  to  work  wrongly 
on  account  of  a similar  misapprehension.  Next  to 
grasping  this  cardinal  point,  we  need  to  realise  the 
extreme  sensitiveness  of  the  etching  baths  to  small 
alterations  of  strength.  Thirty  minims  of  plain  water 


BATH  DILUTION  AND  THE  HYDROMETER 


69 


added  to  two  fluid  ounces  of  etcher  makes  a very  real 
difference  not  only  in  its  rate  of  action,  but  in  its  whole 
characteristics  as  a working  bath.  Hence  not  only 
must  the  Beaume  hydrometer  be  accepted  as  the  high 
priest  of  photogravure  etching  and  its  readings  obeyed 
scrupulously  to  half  a degree,  but  the  hydrometer 
itself  must  be  in  the  first  place  a very  accurate  and 
finely  graded  one.  In  my  own  experience  I bought 
three  at  different  times,  and  tried  them  out  against 
each  other  before  finally  settling  down  to  be  guided  by  a 
special  pre-war  one  discovered  in  the  back  of  a showcase 
in  Penrose’s  process  room.  This  is  graded  in  clearly- 
marked  half  degrees  between  30  and  50  Beaume.  The 
regular  post  war  stock  article  is  not  as  finely  graded, 
and  I doubt  whether  it  is  as  accurate  either.  Should 
photogravure  become  popular  in  the  near  future  there 
is  no  doubt  that  suitable  Beaume  hydrometers  will  soon 
come  upon  the  market.  The  present  price  of  one  is 
about  four  shillings,  and  a testing  glass  to  hold  the 
solution  the  gravity  of  which  is  being  taken  costs 
about  another  half-crown. 

For  a complete  range  of  etching  baths,  which  must 
all  be  made  up  and  ready  at  the  right  temperature 
before  we  start,  sufficient  amounts  of  solution  must  be 
prepared  by  diluting  the  stock  hydrated  solution  to  the 
following  strengths:  41,  40,  39,  38,  37,  36,  35J,  35 
Beaume.  The  worker  had  better  have  a 34  strength 
also,  to  be  on  the  safe  side.  In  my  own  practice  I 
hardly  ever  find  the  need  to  go  below  35,  chiefly  because 
I make  a point  of  preserving  the  utmost  detail  differ- 
entiation in  the  high-lights  of  the  plate  and  keeping 
the  highest  points  of  light  of  all  “ natural,”  which 
is  copper  plate  parlance  for  toneless,  or  undegraded. 


70 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


Enough  of  each  strength  of  bath  should  be  prepared 
to  fill  a three -pound  stone  jam  jar  three-quarters  full, 
and  on  the  front  of  each  jar  I paint  black  enamel 
figures  corresponding  with  the  correct  hydrometer 
reading  of  the  contained  solution — all  except  the 
35 \ bath,  the  jar  of  which  bears  its  strength  marked 


in  red  enamel.  That  is  done  because  it  of  all  baths  is, 
in  my  experience,  the  most  critical.  Sometimes  it 
may  need  to  be  skipped  over,  at  other  times  it  is  called 
upon  for  a prolonged  etching  time  (fig.  20). 

The  jars  should  be  provided  with  tops,  which  may  be 
cleaned-off  half -plate  negative  glasses.  They  keep  out 
dust  and  prevent  undue  evaporation  when  not  in  use. 
A thermometer  must  be  handy  upon  the  etching 
bench,  also  a small  gas  ring  or  electric  heater  with  an 
asbestos  mat  over  it.  Before  the  baths  are  used  they 


Fig.  20. — The  complete  etching  equipment.  The  etching  fluids  are 
contained  in  a row  of  stoneware  jam  jars.  There  is  a sink  and 
water  tap,  a gas  ring  for  heating  the  etching  baths,  a watch  for 
timing,  and  the  paper  and  pencil  for  “ logging  ” etching  times. 


APPOINTMENTS  OF  SIMPLE  ETCHING  BENCH  71 

must  all  be  warmed  to  a working  temperature  not  less 
than  70  F.,  but  possibly  as  high  as  80  F.,  according  to 
the  hardness  of  the  copper.  A copper  that  will  not  start 
under  80  F.  in  moderate  time  with  a normal  thickness 
of  etching  resist  will  be  very  hard,  and — once  you  have 
etched  it  successfully — very  nice  for  printing  from. 
Our  jam  jar  containers  can  be  warmed  by  simply  stand- 
ing them  in  turn  upon  the  safety  asbestos  mat  over 
the  source  of  heat,  and  taking  the  temperature  of  the 
contents  with  the  thermometer,  remembering  also 
that  the  heat  absorbed  by  the  stoneware  itself  will 
bring  about  a further  rise  of  three  or  four  degrees 
Fahrenheit  after  the  jar  has  been  stood  down  on  the 
bench  again. 

For  work  in  comfort  there  should  be  a water  tap  and 
sink  close  by  the  etching  bench,  shown  also  in  fig.  20. 
Failing  that,  provide  a copious  amount  of  wash  water  so 
that  the  plate  may  be  immediately  rinsed  practically 
free  from  perchloride  solution  the  moment  etching  is 
over.  Otherwise  it  will  be  spoiled  even  at  the  moment 
of  its  completion.  A solution  of  washing  soda  makes 
a good  “ stop  bath  5 5 to  the  etching  fluid  if  running 
water  is  not  handy. 

Other  adjuncts  necessary  upon  the  etching  bench  are 
a damp  sponge  or  two  for  keeping  it  clean,  an  area 
marked  off  whereon  to  rest  a lead  pencil  and  some  paper  ' 
and  lastly  some  means  of  timing  the  etching.  If  there 
is  not  a spare  clock  available  having  a minute  hand, 
it  will  be  sufficient  to  do  as  I have  done,  and  knock  a 
nail  into  the  wall  whereupon  you  can  hang  your  watch 
where  it  will  be  at  once  ready  to  consult  and  out  of  the 
way  of  possible  splashes  of  etching  fluid. 


CHAPTER  X 


An  etching  “ log  ” and  how  to  keep  it. 

The  obvious  purpose  of  the  pencil  and  paper  is  for 
keeping  a “ log  ” of  the  times  of  the  plate’s  immersion 
in  the  various  etching  baths.  To  do  this  is  a matter  of 
highest  importance.  The  paper  may  conveniently  have 
written  at  the  head  of  it  the  date,  size  of  plate,  subject, 
and  whether  it  is  the  first  plate  etched  of  that  subject, 
or  whether  a second  or  subsequent  attempt.  Under 
this  heading  my  practice  is  to  write  the  word  “ IN  ” 
at  the  extreme  left-hand  side  of  the  sheet.  Time 
(of  day)  of  the  plate’s  immersion  (accurate  to  the 
half  minute)  is  duly  written  against  this  and  underneath 
in  a parallel  column  is  placed  the  figure  representing 
the  gravity  of  the  etching  solution  to  which  the  time 
refers.  Immediately  on  pouring  off  an  etching  bath 
and  substituting  another  the  time  and  gravity  of  the 
new  bath  are  similarly  added  in  parallel  columns, 
and  so  on  till  the  plate’s  etching  is  complete,  when  I 


Size  6x4.  Boat  on  the  Beach  (2nd  plate).  G 12  tissue.  Oct.,  1924. 

Very  hard  copper. 

Times.  ^44.S-^ 

In  4.35  P.M. — 41 1 48—54—59—5.4  P.M.^ 

Bath  strengths.  0U^‘ 

40 39 38—37—36 ^ 


Pig.  21a. — Specimen  etching  log  of  an  average  straightforward  plate. 
Note  that  actual  time  of  etch  is  time  from  start  of  etching  (black 
type)  to  out — in  this  instance  just  20  minutes.  Result,  a good  plate. 

72 


“ LOGGING  ” PROGRESS  OF  ETCHING 


73 


bracket  both  columns  together  and  write  the  word 
“ OUT  ” (fig.  21a). 

It  by  no  means  follows  that  all  the  etching  will 
progress  along  a sequence  of  baths  each  of  which  is 
weaker  than  the  last.  Quite  often  the  desired  effect 
can  best  be  got,  or  can  only  be  got,  by  returning  to  a 
stronger  bath  after  a weaker  one.  To  denote  this  we 


G 12  t'ssue.  Oct.,  1924. 
8x5.  Landscape  near  Neivquay.  From  contact  transparency- 

on  stripping  film. 

Very  hard  copper, 

^lO.S^ 

In  12.51  P.M.-1.3-7  14 19—22—26—31-35—39—40^ 

I out 

41 40—39 ^ 4(}  ^ 39-  38— 37— 36— 35|-^4  f ^ 


Fig.  21b.- — Specimen  etching  log  of  a tricky  plate  that  required  two 
returns  to  stronger  baths.  The  return  to  a stronger  bath  is  denoted 
by  a downward  dip  of  the  log  line.  Actual  etching  time,  30  minutes. 
Result,  plate  deeply  etched  but  satisfactory. 


need  some  simple  and  quickly  “ loggable  ” code  sign. 
My  way  is  to  draw  a line  dipping  down  well  below  the 
general  level  of  the  line  upon  which  gravities  are 
recorded  and  to  enter  up  the  stronger  gravity  at  the 
foot  of  this  line  (fig.  21b).  Any  other  convenient  code 
marking  for  this  or  any  of  the  logging  will  do  just  as 
well  of  course,  the  important  point  being  to  start 
some  adequate  time  and  bath  recording  system  with 
the  very  first  plate  attempted.  Only  by  frequent 
comparison  of  previous  etching  times  and  strengths 
can  a worker  rapidly  acquire  useful  knowledge  of  what 
gradation  range  he  may  expect  from  any  bath  or 
sequence  of  baths.  For  the  etching  of  the  copper  is 


F 


74 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


as  the  development  of  a photographic  negative  where 
two  or  more  different  developers  are  employed  each 
for  selective  rendering  of  density  or  detail,  except  that 
no  dual  or  triple  bath  negative  development  ever  yet 
presented  the  complication,  difficulty,  and  oppor- 
tunity for  wide  control  through  seemingly  trifling 
modification  that  you  will  find  in  etching  a photo- 
gravure printing  plate. 


CHAPTER  XI 


Etching  with  graduated  bath  strengths.  Characteristics 
of  the  various  baths  described.  Judging  indications 
of  the  start,  progress  and  finishing  point  of  etching. 

Start  (if  in  doubt)  with  bath  41,  and  leave  the  plate 
in  it  for  two  or  three  minutes.  Pour  on  enough  solu- 
tion to  keep  the  resist  covered  all  the  time  the  bath 
is  rocked.  It  needs  no  more  than  quite  gentle  rocking. 
Just  previous  to  putting  the  plate  in  the  etching  bath 
fan  it  over  the  heater  for  half  a minute  to  dry  out 
the  resist  thoroughly  and  evenly  in  case  it  should 
have  absorbed  traces  of  atmospheric  moisture  between 
now  and  when  it  was  dried  after  development.  Do 
not  be  surprised  if  bath  41  fails  to  etch  the  plate  at 
all.  Generally  it  has  no  action. 

How  to  know  whether  it  is  etching  ? You  can  tell 
that  fairly  definitely  because  as  soon  as  the  copper 
begins  to  be  attacked  in  the  deepest  shadows  the 
hitherto  bright  metallic  copper  surface  goes  black, 
green-black  or  brown-black,  according  to  the  sort  of 
copper  being  etched.  You  can  see  the  dark  shadow 
representing  actual  shadow  in  the  plate  start  up  fairly 
suddenly  and  with  remarkably  clean-cut  outlines. 
Start  of  etching  should  at  once  be  “ logged  on  the 
etching  sheet,  my  code  being  the  time  written  within 
a pencilled  circle,  with  the  letter  S attached  to  it,  no 
corresponding  change  of  bath  strength  appearing  in 

75 


76 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


the  parallel  line  below  (see  figs.  21a  and  21b).  In 
the  log,  as  here  printed,  the  starting  time  is  shown  in 
heavy  type  instead  of  being  “ ringed.” 

Necessity  to  log  start  of  etching,  as  well  as  time  of 
original  immersion  of  the  plate  in  the  etcher,  arises 
from  the  fact  that  though  the  various  times  in  the 
various  bath  strengths  which  follow  are  for  us  to 
determine  through  the  exercise  of  our  own  skill,  total 
etching  time  for  a particular  grade  of  copper  is  a 
fixed  quantity  within  quite  narrow  limits.  In  screen 
photogravure  the  plate  should  not  be  etched  for  less 
than  twenty  nor  for  more  than  twenty-five  to  twenty- 
seven  minutes  for  hard  copper  and  a good  average 
printing  depth  with  “ rag  wiping.”  Etching  time  is 
time  from  start  to  completion  of  etching.  Where  a 
plate  is  sluggish  in  showing  its  first  change  of  colour 
this  time  may  be  very  different  from  that  between 
plate  immersion  and  completion  of  etching. 

Should  the  copper  show  colour  change  within  three 
minutes  in  the  41  bath  it  is  a sign  that  the  resist  is 
thin,  that  the  copper  is  soft  or  the  etching  temperature 
too  high.  However,  continue  with  the  same  bath  until 
the  darkening  involves  what  are  to  be  the  deepest  out- 
lines of  our  subject  ; that  is  those  outlines  which,  if 
we  were  drawing  them  in  on  paper,  would  have  been 
marked  with  the  full  depth  of  a soft  pencil.  Imme- 
diately the  plate  gets  that  far,  change  to  bath  40,  log 
the  change  and  the  time  of  it  and  carry  on,  watching 
narrowly  while  darkening  of  the  copper  underneath 
the  resist  extends  to  the  next  deepest  set  of  shadow 
tones.  That  is  the  regular  way  of  it,  and  all  I can  do 
to  aid  you  further  at  this  point  is  to  give  some  general 
hints  which  may  or  may  not  prove  to  fit  in  well  with 


BATHS  AND  THEIR  ETCHING  LIMITS 


77 


the  technique  it  is  up  to  you  to  elaborate  for  yourself, 
by  trial  and  error. 

Bath  41.  Seldom  calls  for  an  etching  time  of  more 
than  three  minutes  after  first  signs  of  darkening  of  the 
copper.  Where  heavy-printing  shadows  are  not  of 
first  importance  in  the  plate  this  bath  may  even  be 
done  without  altogether,  beginning  etching  routine 
with  bath  40  instead.  Most  of  my  own  plates  make 
no  appreciable  start  of  etching  in  bath  41. 

Bath  40.  An  important  bath  and  usually  the  one 
which  seriously  starts  the  etch,  especially  with  extra- 
hard  copper.  A usual  time  to  allow  in  this  bath 
after  start  of  etching  is  three  to  four  minutes,  but  it 
is  generally  worth  while  waiting  for  eight  or  nine 
minutes  if  necessary  to  give  a hard  copper  plate  a 
chance  to  start  in  bath  40,  where,  for  some  reason,  such 
as  thickness  of  the  resist,  it  will  not  get  a move  on 
before.  The  average  three  minute  etching  time  is, 
as  already  explained,  a timing  taken  from  the  moment 
of  first  copper  darkening. 

Bath  39.  This  bath  also  will  tackle  deep  shadow 
tones  and  is  the  last  of  the  series  which  can  be  depended 
upon  to  do  so.  Some  quite  good  plates  only  make 
their  start  of  etching  in  the  39  strength  bath.  In 
that  event  the  etch  in  this  strength  of  solution  should 
be  continued  for  six  or  seven  minutes.  Where  the 
40  bath  has  previously  acted  normally,  etching  time 
in  39  may  be  anything  from  two  to  four  minutes, 
according  to  the  characteristics  of  the  plate. 

Bath  38.  This  is  the  general  purpose  bath  of  the 
etching  series.  Authorities  say  that  whereas  the 
stronger  baths  must  only  be  used  sparingly,  to  etch 
deep  shadows  and  more  or  less  to  outline  the  image, 


78 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


bath  38  should  be  pushed  pretty  well  to  the  limit  of 
etching  That  might  mean  an  etching  time  approach- 
ing eight  minutes.  Personally  I have  not  found  so 
good  a result  from  pushing  the  38  bath  with  G 12 
tissue  as  other  workers  appear  to  do,  though  readers 
wilh  understand  I make  no  pretence  to  be  more  than 
an  interested  learner  myself.  I favour  four  or  five 
minutes  as  the  average  for  38.  This  is  the  bath  for 
etching  the  deeper  mid-tones. 

Bath  37.  In  my  own  experience  this  and  bath  36 
are  key  baths  of  the  process.  In  37  you  get  out  those 
mid-mid-tones  which  do  most  to  richen  and  round  off 
the  general  detail.  Generally  my  aim  is  to  give  not  less 
than  four  minutes  here.  Sometimes  I have  gone  to 
seven  or  eight  minutes,  and  been  glad  of  it  afterwards. 

Bath  36.  A high-light  detail  forming  bath.  To  36 
generally  comes  the  business  of  etching  the  more 
accentuated  shadows  of  cloud  forms  and  of  other  parts 
of  the  plate  having  similar  position  in  the  “ light 
grey  ” end  of  the  tonal  scale.  Bath  36  is  the  final 
bath  with  some  plates  where  great  accentuation  of 
the  lighter  detail  is  called  for  and  where  the  resist 
has  been  rather  thinly  printed.  On  these  occasions 
the  etch  in  it  may  be  prolonged  to  eight  or  ten  minutes. 
Where,  as  normally,  the  plate  is  to  be  transferred  to  a 
weaker  bath  etching  time  will  be  probably  abouf  five 
minutes,  but  seldom  less  than  four. 

Bath  35 1 . This  is  the  final  bath  for  many  of  my 
plates,  taking  the  place  of  35,  which  in  my  experience 
has  a habit  of  rushing  the  faintest  high-light  details 
together  till  they  become  clogged  with  a general 
printing  tint  over  the  plate.  From  three  to  five 
minutes  in  35|-  usually  brings  us  to  the  final  point 


DILUTEE  BATHS  CHARACTERISTICS 


79 


where  faint  evidence  of  darkening  of  the  copper  can 
be  seen  underlying  all  but  the  thickest  parts  of  the 
resist.  Where  the  highest  lights  appear  quite  un- 
changed after  five  to  six  minutes  in  35J  the  plate  can 
be  passed  on  to  35  bath, 

Bath  35.  With  me  the  high -lights  “ go  through  ” 
with  something  of  a rush.  This  bath  I have  found 
of  little  use  for  differentiation  of  'detail,  but  it  supplies 
that  slight  extra  rounding  at  the  edges  of  rather  faint 
shadows  which  is  invaluable  in  some  subjects.  Usually 
three  minutes  in  35  brings  out  everything,  and  much 
longer  etching  time  here  causes  the  plate  to  take 
printing  depth  in  the  parts  which  should  proof  white, 
so  that  the  whole  tone  rendering  is  flattened  and  foggy 
looking  prints  are  given  by  plates  wherein  this  bath’s 
timing  is  overdone.  The  rule  for  the  end  point  in 
photogravure  is  to  give  half  a minute  after  the  highest 
tone  of  the  plate  to  be  etched  appears  to  have  started 
biting,  as  well  as  can  be  judged  by  looking  on  the  face 
of  the  resist. 

Bath  34.  All  I can  say  about  this  bath  is  that 
I hardly  ever  find  the  necessity  for  it.  At  the  same 
time  other  workers  tell  me  they  do  so,  and  though 
I may  suspect  the  truth  to  be  that  their  hydrometers 
are  graduated  with  a one  degree  error  on  the  high 
side,  it  would  be  unseemly  to  deny  the  faint  possi- 
bility that  all  of  mine  are  graduated  with  a similar 
error  on  the  low  side.  Or  it  may  be  just  cussedness  on 
the  part  of  my  copper  piates  or  a tendency  on  my  part 
to  keep  the  temperature  of  my  etching  solutions 
nearer  to  80  than  to  70  Fahr. 

To  the  experimenter  I would  say,  therefore,  have 
bath  34  ready  in  case  you  need  it,  remembering  that, 


80 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


unlike  the  development  of  a negative,  once  the  etching 
of  a photogravure  plate  has  been  commenced  it  must 
be  gone  through  with , right  from  start  to  finish.  You 
cannot  stop  in  the  middle  and  take  up  the  work  again 
at  a future  time.  You  cannot  delay  the  plate  for 
even  a minute.  If  you  dry  the  resist  it  is  done  for  as 
a resist.  If  you  soak  the  partly  etched  plate  in  plain 
water,  that  does  for  the  resist  also.  Once  in  the  first 
bath  you  can  simply  do  nothing  else  whatever  than 
go  right  on  till  the  etch  is  complete.  You  know  before- 
hand what  time  to  allot  for  it — twenty-five  minutes 
from  start  of  etching  or,  say,  a maximum  time  of 
three-quarters  of  an  hour  from  first  immersion  of  the 
plate. 

When  you  judge  etching  to  be  complete  take  the 
plate  and  swill  it  rapidly  and  thoroughly  under  the 
tap.  Alternatively,  rinse  it  for  a second  or  two  in  a 
large  dish  of  plain  water  and  transfer  it  to  a second 
* dish  containing  the  “ stop  bath  ” : a cold  solution  of 
washing  soda  (soda  carbonate).  After  that  the  resist 
may  be  cleaned  off  at  leisure.  The  implement  I find 
most  handy  is  a tooth  brush  having  long  and  strong 
bristles.  Doubtless  a nail  brush  would  do  quite  well. 
And  bear  in  mind  from  now  on  your  chief  enemy  is 
grit.  Every  scratch  upon  the  plate’s  surface  above  a 
certain  depth  will  be  a future  ink-holding  rut  which 
will  print  in  the  press  as  a hair-line  upon  your  proofs. 

The  above  notes  refer  more  particularly  to  G 12 
and  G 7 tissue.  G 15  requires  slightly  stronger  baths 
for  the  final  etches,  but  the  range  already  indicated 
will  suit  with  very  small  modification  of  etching  times. 


CHAPTER  XII 


Etching  troubles  ; their  meaning  and  avoidance.  When 
to  retrace  from  weak  baths  to  stronger  and  a 
suggested  code  for  “ logging  ” this  retraction . 
Distinctive  behaviour  of  new  baths  and  old. 

The  last  chapter  attempted  to  give  a useful  sketch 
of  the  normal  etching  procedure,  taken  at  its  happiest. 
It  is  not  always  as  plain  sailing  as  there  represented. 
Of  this  I will  now  tell.  Rut  first  it  may  be  helpful  to 
give  a specimen  computation  of  times  for  the  various 
baths  for  two  typical  resist  printings. 

The  time  “ log  ” for  average  etching  where  the 
resultant  plate  possessed  a long  and  even  tonal  scale 
shows  : Time  in  bath  41  before  start  of  etch,  three 
minutes.  Copper  seen  to  have  begun  a slight  colour 
change  in  deepest  shadows,  so  etching  time  prolonged 
another  two  minutes.  Colour  change  still  very  slight. 
Plate  removed  to  bath  40  for  three  minutes,  and  thence 
onward  to  39  for  three  minutes  ; 38,  four  minutes  ; 
37,  four  minutes  ; 36,  five  minutes  ; 35J,  four  minutes 
and  out.  Total  etching  time  : twenty-five  minutes. 

Example  two  is  of  a seascape  the  chief  feature  of 
which  is  the  tonal  rendering  of  breaking  waves,  deepest 
shadows  in  this  plate  being  represented  only  by  some 
fishing  boats  in  the  middle  distance.  Here  etching 
started  in  bath  39  and  was  continued  therein  for  seven 
minutes.  In  bath  38  the  plate  had  only  three  minutes, 

81 


82 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


in  37  it  had  six  minutes,  in  36  another  six  minutes 
and  out.  Total  etching  time  22  minutes.  You  will 
perceive  the  times  were  chosen,  firstly  to  get  the  greatest 
possible  depth  into  the  printing  of  the  distant  fishing 
boats,  next  to  make  an  intentional  step  to  the  much 
lighter  tones  of  the  waves,  thirdly  to  emphasise  cloud 
forms  in  the  sky  of  the  picture  to  the  uttermost. 

These  two  examples  fairly  well  show  how  individual 
judgment  is  to  be  used  in  etching,  according  to  the 
subject  dealt  with. 

Now  to  consider  cases  where  a straight  sequence  of 
baths  is  not  adequate  to  the  proper  rendering  of  the 
subject.  It  may  happen  that  etching  fails  to  start 
until  a plate  has  got  to  bath  39,  then  makes  a rush, 
several  tonal  values  showing  signs  of  coming  through 
rapidly  one  on  top  of  another.  The  thing  to  do  here  is 
to  tip  off  39  and  substitute  41  without  a moment’s 
unnecessary  delay.  Keep  41  on  the  plate  until  the 
tones  appear  to  have  separated  sufficiently,  then  pass 
on  for  a minute  or  so  to  40  and  back  into  39, 
from  which  point  the  usual  progress  of  etching  may 
proceed. 

Another  problem  may  arise  in  that  while  the  tones  of 
the  plate  etch  regularly  you  have  reason  to  suspect 
that,  possibly  as  a result  of  a slightly  flat  transparency, 
the  completed  plate  as  a whole  will  be  lacking  in 
richness  in  its  deeper  half-tones  and  shadows.  That 
may  be  combated  by  returning  the  plate  for  a minute 
or  so  to  the  40,  or  even  to  the  41  bath,  after  re- 
moval from  what  would  ordinarily  be  the  final  bath  of 
the  etch.  The  40  bath  thus  becomes  the  final  bath. 
Used  so,  one  minute  is  generally  sufficient  for  it, 
while  the  two-minute  time  should  not  be  exceeded  or 


“ ROLLING  TIP,”  A FORLORN  HOPE  83 

mid-tones  will  be  made  heavy  and  the  plate  will  print 
with  an  over-loaded  look. 

Etching  in  photogravure  provides  no  opportunities 
for  a similar  practice  to  the  “ fine  etching  ” of  half-tone 
typographic  block  making,  but  a thin  plate  may  be 
strengthened  in  its  shadow  and  deeper  mid-tones,  after 
removal  of  the  resist,  by  re-etching.  To  do  that  you 
need  an  inking  slab,  such  as  an  old  smooth  litho  stone, 
some  “ finishing  ink”  (to  be  had  at  process  engraver’s 
supply  stores),  spirit  of  turpentine  and  a “glazed 
roller.”  The  ink  is  thinned  well  down  with  turpentine, 
distributed  very  thinly  upon  the  stone  with  the  glazed 
roller,  and  the  roller  is  passed  over  the  surface  of  the 
etched  plate  until  an  even  film  of  finishing  ink  has 
been  deposited  on  all  but  the  deeper  etched 
hollows.  As  soon  as  the  turpentine  has  evaporated 
the  plate  may  be  given  a one  minute  etch  in  38  bath. 
For  better  protection  of  the  inked  surface  it  may  be 
dusted  lightly  with  powdered  bitumen,  excess  being 
carefully  removed  with  a camel  hair  mop,  and  the  plate 
being  warmed  till  the  adhering  bitumen  powder  takes 
a slight  shine.  I mention  this  partly  because  it  is  the 
one  process  of  ordinary  photo -engraving  which  seems 
to  be  adaptable  to  photogravure.  But  since  good 
glazed  rollers  are  almost  as  difficult  to  come  by  as  auk’s 
eggs,  and  since  no  other  kind  can  be  depended  on,  few 
photographers  will  be  likely  to  go  in  for  “ re -etching  ” 
weak-printing  plates.  Besides,  it  is  far  better  to  scrap 
and  re -make  them. 

There  remain  a few  more  things  about  plate  etching 
which  I would  like  to  mention.  I have  warned  readers 
in  an  earlier  part  of  my  discourse  that  different  samples 
of  copper  do  not  behave  alike,  either  in  their  etching 


84 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


colour  or  in  the  rapidity  with  which  the  ferric  chloride 
solution  does  its  work  upon  them.  Soft  copper  gener- 
ally shows  a very  full  deep  black  colouration  from 
start  to  finish  of  etching.  Also  it  is  acted  upon  strongly 
with  the  more  concentrated  baths  and  may  run  ahead 
of  the  etcher  when  getting  toward  the  end.  Total 
etching  time  with  such  copper  will  probably  not  be 
over  twenty  minutes,  and  instead  of  baths  38  and  37 
needing  to  be  pushed  far  they  may  need  to  be  curtailed. 
In  that  event  36  will  likely  enough  become  the  end 
bath  of  the  series.  Where  the  first  plate  of  a new  batch 


10  x 7.  Swan  on  Water.  G 15  tissue.  January,  1925. 

Medium  copper. 

In  7 P.M. — 7.2 — 7.7  13—15—19—22—25—27—^ 

out. 

4 1 40—39 38-37—36—351-35 — ^ 


Fig.  21c. — Specimen  etching  log  showing  how  grade  of  copper  influences 
etching  time.  This  plate  on  medium  hard  copper  was  fully  etched 
in  16  minutes.  Result,  a good  plate. 


of  copper  shows  the  start  of  etch  eartyon,  in  41  or  almost 
immediately  after  transfer  to  40,  and  where  resist  and 
temperature  seem  to  be  average,  soft  metal  should 
be  suspected  as  the  cause.  Copious  floating  off  of  a deep, 
black  stain  from  the  surface  of  the  resist  is  a sign  of 
equivalently  deep  etching  going  on  beneath  it.  This 
is  often  a premonitory^  sign  of  the  etching  running  ahead 
of  you.  The  specimen  etching  log  (fig.  21c)  is  of  an 
actual  plate  on  rather  soft  copper  which  took  only  16 
minutes  for  full  depth. 

Finally,  we  must  know  the  distinctive  characteristics 
of  new  and  much  used  etching  solutions.  A new  bath 


NEW  AND  SPENT  BATH  PECULIARITIES 


85 


tends  to  etch  shadow  detail  deeply  in  the  greater 
strengths.  In  the  lesser  strengths  the  tendency  is 
for  it  to  bite  through  various  lighter  tones  too  closely 
together,  so  that  the  finished  plate  prints  at  once 
heavy  and  flat.  A usual  way  of  correcting  this  is  to 
get  a little  copper  into  the  etching  fluid,  either  by 
allowing  it  to  act  upon  an  unwanted  copper  plate  for  a 
few  minutes  before  it  is  taken  into  regular  use,  or  by 
retaining  a little  of  your  old  etching  baths  and  adding 
some  to  the  bulk  of  new  baths  intended  to  replace 
them. 

Naturally  we  shall  look  for  exactly  the  reverse 
characteristics  in  old  and  worn  out  etching  solutions. 
With  these  the  stronger,  earlier,  baths  fail  to  bite 
deeply  enough,  while  late  baths  have  a way  of  stopping 
short  suddenly  at  a certain  tone  graduation,  and  tending 
to  over-emphasise  it  by  too -deep  biting  before  passing 
on  to  the  next  lighter  tone.  They  are  over-selective. 
My  advice  to  the  worker,  at  the  start  at  any  rate,  is  to 
avoid  trouble  from  over-worked  baths  by  making  up 
new  ones  at  frequent  intervals,  always  adding  to  them 
about  one-tenth  part  of  the  discarded  bath  of  equivalent 
strength  before  taking  into  use.  Ferric  chloride  is 
cheap.  Its  cost  in  London  is  something  less  than 
sixpence  a pound. 

Never  omit  to  check  the  specific  gravity  of  every 
strength  of  working  bath  with  the  Beaume  hydrometer 
the  first  thing  on  each  day  of  etching,  and  correct  it 
without  fail  by  adding  water  or  concentrated  stock 
etching  solution,  as  may  be  necessary.  The  tendency 
is  for  the  contents  of  the  etching  jars  to  settle  towards 
some  middle  concentration  depending  upon  the  time 
of  year  and  climatic  conditions  of  the  locality.  Strong 


86 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


baths  tend  to  weaken  with  standing,  through  absorp- 
tion of  water  vapour  from  the  air,  while  weak  ones 
concentrate  themselves  by  evaporation.  Forgetting 
or  neglecting  this  is  a certain  cause  of  erratic  and  out- 
of-control  etching. 


CHAPTER  XIII 


Describes  how  to  clean  the  etched  plate  and  prepare  it 
for  printing.  With  some  hints  on  hand  control 
for  those  who  are  able  and  willing  to  make  use  of  them. 

When  we  have  gently  rubbed  off  the  resist  from  the 
etched  plate,  what  do  we  see  ? We  see  an  awful- 
looking  muddle  of  smudge  and  stain  (fig.  19).  Were  it 
not  that  Denison  had  duly  prepared  me  for  this  in  his 
excellent  text-book  I might  easily  have  thought  it 
useless  attempting  to  proof  my  first  plate  at  all.  The 
reason  why  nothing  definite  appears  at  once  is  because 
the  whole  depth  of  etching,  even  in  the  deepest  hollows 
of  a photogravure  plate,  is  not  comparable  with  the 
etching  depth  of  even  a shallow  typographic  half-tone 
block.  In  the  mid-tones  depth  is,  of  course,  still  less. 
As  against  it,  all  the  plate  surface,  barring  inconsider- 
able expanses  here  and  there,  has  been  acted  upon  by  the 
etching  baths  sufficiently  to  have  taken  surface  stain. 

The  thing  to  do,  therefore,  is  first  of  all  to  remove 
the  whole  of  the  acid  resist  varnish  from  rim,  edges,  and 
back  of  the  plate.  If  any  spotting  has  been  done 
with  this  varnish  on  the  plate’s  surface  it  must  be  got 
rid  of  also.  A wipe  over  with  benzine  or  petrol  applied 
on  a clean,  soft,  grit-free  rag  will  soon  bare  the  copper. 
Follow  with  a gentle  application,  upon  another  clean 
linen  rag,  of  a thin  paste  of  double -washed  whiting 
and  water.  Personally,  I find  the  next  few  moments  as 

87 


88 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


exciting  as  any  in  the  whole  procedure,  for,  as  the 
whiting  takes  the  general  stain  away,  the  image  makes 
its  first  appearance  as  a very  beautiful  picture  upon  the 
bright  copper  background  (fig.  22).  After  a few  plates 
have  been  made  it  becomes  fairly  easy  to  tell  from  the 
appearance  of  the  cleaned -up  etched  image  whether 
we  have  or  have  not  scored  at  least  moderate  success. 


Fig.  22. — -The  same  plate  seen  in  Fig.  19,  but  now  the  bitumen  resist 
border  has  been  cleaned  off  with  petrol  and  the  surface  of  the 
copper  polished  with  a gentle  application  of  whiting  and  water. 


The  deepest  parts  of  an  average  plate  will  not  be 
reached  by  the  whiting,  so  that  shadows  will  show 
dark  upon  the  light  metal.  This  makes  judgment 
the  easier,  but  some  of  the  published  instructions 
advise  removal  of  the  deeper-seated  darkening  in 
photogravure  plates  by  treatment  oi  the  copper  with 
a very  dilute  chemical  cleaner  of  the  sort  already 


CLEANING  AND  SMOOTHING  THE  PLATE 


89 


mentioned  as  a possible  bath  for  removing  tarnish  from 
plates  previous  to  making  them  ready  for  the  tissue. 
The  bath  for  etched  plates  contains  one  quarter  of  a 
dram  each  of  sulphuric  acid  and  chromic  acid  to  the 
pint  of  water.  If  it  is  used,  the  plate  should  be  put  in 
it,  and  dark  portions  gently  scrubbed  with  the  tooth- 
brush, taking  the  plate  out  again,  and  rinsing  it  well 
as  soon  as  ever  slmdow-stain  is  gone.  But  I do  not 
myself  care  for  the  treatment.  Undoubtedly  it  removes 
copper  from  the  thinner  printing  depths  as  well  as 
taking  stain  out  of  the  hollows  representing  shadow 
tones.  However,  the  chromic  bath  may  sometimes 
be  used  with  advantage  where  a plate  has  previously 
been  etched  a shade  too  far. 

We  have  still  to  get  the  edge  of  the  plate  smooth. 
I mean  by  that  the  edge , not  the  rim , which,  if  the 
resist  varnish  has  been  properly  applied,  will  be  smooth 
in  any  case.  Whether  the  edge  also  is  smooth  will 
depend  upon  luck,  perhaps,  or  upon  whether  a bevelled 
plate  was  bought  in  the  first  place.  As  bevelled  plates 
cost  one-quarter  as  much  again  as  unbevelled  ones,  I 
have  never  myself  afforded  them.  A simple  way  to 
smooth  off  the  edge  of  a rough-cut  plate  is  to  moisten 
a slip  of  fine  carborundum  stone  and  rub  it  over  the 
copper  until  the  metal  has  been  taken  down  smooth 
and  slightly  rounded  off.  Artist  etchers  are  accus- 
tomed to  bevel  their  hand-engraved  plates  for  them- 
selves by  first  rasping  down  the  metal  about  the  rim 
and  then  smoothing  and  polishing  it  with  pumice 
powder  and  rouge.  A good  way  to  apply  the  rouge 
is  upon  a fiat  leather  covered  slip  of  wood.  A snake - 
stone  slip  is  very  useful  for  the  smoothing  of  plate 
edges, 
a 


90 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


If  the  resist  we  have  etched  was  a perfect  one,  we 
shall  not  need  to  do  any  hand  touching-up  to  remove 
blemishes.  Where  any  spotting  with  varnish  had 
previously  been  necessary,  the  plate  will  show  small 
corresponding  unetched  areas  which  will  print  white 
unless  they  are  converted  to  ink-holding  surfaces  by 


Fig.  23. — Head  of  a roulette  enlarged  12  times.  The 
original  spurs  are  150  to  the  inch  on  the  rim  of 
the  pivoted  wheel. 

touching-up  with  a dry-point  needle  or  a roulette. 
The  drjr-point  needle  is  a steel-pointed  graving  instru- 
ment with  which  a fine  cross-hatching  of  lines  may  be 
scratched  in  the  copper.  Roulettes  are  little  wheels 
fitted  upon  handles.  Each  wheel  is  made  of  hardened 
steel,  and  has  upon  its  rim  a series  of  raised  points  at 
intervals  corresponding  with  the  ruling  of  the  photo- 
gravure screen  (fig.  23).  If  the  roulette  is  run  firmly, 
but  not  over-hard,  over  the  copper  it  presses  its  track 
permanently  into  the  surface  of  the  plate,  the  depres- 
sions being  amply  deep  enough  to  hold  a good  deal  of 


HAND  ENGRAVING  FINAL  TOUCHES  91 

ink  when  the  plate  comes  to  be  proofed.  The  rule 
is  (as  far  as  my  own  experience  goes)  to  put  in,  or  to 
emphasise,  light  mid-tones  with  the  dry-point  and 
dark  mid-  and  shadow-tones  with  the  roulette. 

After  using  either  of  them,  the  engraved  part  of 
the  plate  must  be  very  gently  gone  over  with  the 
burnisher  and  a little  oil  or  water,  to  take  down  what- 
ever burr  has  been  formed.  Burnishing  after  touching- 
up  very  much  lessens  the  ink-holding  strength  of 
whatever  hand- work  has  been  done,  but  if  you  depend 
upon  the  burr  to  reinforce  it  (as  it  will  do),  you  have  a 
plate  that  cannot  be  relied  upon  to  print  the  same 
strength  in  the  touched-up  portions  many  times  over. 
The  burr  gradually  subsides  of  itself  under  repeated 
pressure  in  the  copper  plate  press,  and  coincidentally 
these  touched  out  defects  become  once  again  apparent. 

There  is  even  the  possibility  of  exercising  broad 
control  in  the  printing  tones  of  an  etched  photo- 
gravure plate  by  cautious  local  application  of  brass 
polish.  When  I do  this  I give  the  liquid  metal  polish 
a shake  up,  and  let  it  stand  a minute  for  the  heavier 
grit  to  subside  to  the  bottom  of  the  tin  before  pouring 
out  the  polish  for  use.  Those  who  are  familiar  with 
Baskett’s  reducer  for  negatives,  or  Bruce’s  “ Nega- 
fake,”  will  have  no  difficulty  in  seeing  the  similar 
possibilities  of,  say,  Brasso,  upon  copper  plates.  For 
putting  in  small  touches  of  lighter  tone  here  and  there, 
instead  of  using  brass  polish,  a slip  of  wood  charcoal 
may  be  moistened  with  water  and  rubbed  upon  the 
metal  in  the  same  way  as  a “ Negafake  ” pencil. 
Anyone  good  at  creating  cloud  forms  has  by  this  means 
a further  outlet  for  his  talent. 

A five  inch  by  one  quarter  inch  slip  of  snakestone  is 


92 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


another  invaluable  help  to  touching  up  gravure  plates 
by  hand.  Use  it  moistened  with  water.  It  grinds 
away  the  copper  without  sensibly  roughening  the 
surface.  While  wet  willow  charcoal  lightens  heavy 
tones  without  greatly  disturbing  light  half-tones,  wet 
snakestone  does  the  reverse,  removing  light  half-tones 
and  preserving  the  heavier  shadows. 


CHAPTER  XIV 


An  alternative  etching  system — by  bath  dilution — of  value 
to  the  experienced  worker  and  with  more  particular 
application  to  rotary  gravure.  Gravure  plates  from 
ink  and  pencil  drawings. 

You  have  heard  of  the  regular  way  of  plate  etching, 
with  the  row  of  jars  of  ferric  chloride  solution  ranging 
in  their  specific  gravities  from  41  to  34  Beaume, 
dropping  by  single  degrees,  or  even  by  half  a degree, 
in  strength.  You  need  not  go  to  nearly  so  great  an 
elaboration  unless  you  like,  though  you  will  certainly 
work  more  methodically  and  have  a far  bigger  chance 
of  learning  the  technique  of  etching  well  if  you  do. 
There  is  a simple  alternative  all  the  same.  The 
present  chapter  shall  set  it  forth  and  will  add  a few 
hints  on  the  reproduction  in  photogravure  of  line 
drawings. 

On  the  alternative  etching  system  you  make  up 
one  bath  strength  only,  which  may  conveniently  be 
40  Beaume.  Pour  out  into  a measure  enough  of  this 
to  cover  the  plate  in  its  etching  dish,  and  note  care- 
fully how  much  you  pour.  Bring  its  temperature  to 
whatever  may  be  your  favourite  thermometer  read- 
ing, whether  70  deg.  or  75  deg.  Fahr.  Have  also  ready 
a second  measure  of  clean  water  brought  to  the  same 
temperature.  Pour  the  40  strength  bath  on  the 
copper  plate,  rock  gently  and  time  with  watch  or 
clock  up  to  seven  or  eight  minutes  if  necessary  till 

93 


94 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


etching  starts,  and  thence  forward  for  another  two  or 
three  minutes  to  get  your  shadow  tone  outlines,  as 
already  described.  Then  tip  the  etch  back  into  its 
measure  and  add  w^ater  in  proportion  of  one  dram 
water  to  each  four  ounces  of  etching  fluid.  Stir 
quickly  and  thoroughly  and  at  once  pour  the  diluted 
bath  back  on  the  plate  for  a further  twTo  or  three 
minutes’  etch.  When  the  next  step  in  biting  the 
plate  seems  to  have  proceeded  sufficiently  far  for 
prudence,  once  more  return  the  etch  to  the  measure, 
add  another  dram  of  water,  stir  and  return  to  the 
plate  again.  Do  this  at  your  own  discretion  until  the 
plate  is  fully  etched,  adding  always  the  one  dram  of 
water  at  a time,  but  choosing  your  etching  periods  to 
please  yourself. 

A strong  point  about  this  technique,  from  the 
standpoint  of  an  expert,  is  the  fine  grading  of  bath 
strengths  which  it  admits  of.  Instead  of  jumping 
down  degree  by  degree,  the  general  principle  can  be 
so  adapted  that  steps  in  the  etching  process  are 
merged  very  completely  into  one  another,  rounding 
of  tones  and  length  of  tone  scale  in  the  plate  being 
improved  accordingly. 

For  beginners,  the  dilution  system  also  possesses  a 
great  advantage  in  its  simplicity  of  application.  You 
do  not  need  a row  of  separate  jars,  each  of  which  has 
to  be  labelled,  each  one  warmed  to  correct  temperature 
and  each  tested  and  adjusted  accurately  to  strength 
whenever  etching  is  going  to  be  started.  There  is 
great  saving  of  bench  space.  The  counter- weighting 
disadvantage  is  that  neither  do  you  know  exactly 
what  specific  gravity  of  etching  fluid  is  responsible  for 
each  portion  of  the  tonal  scale  of  the  finished  plate, 


ETCHING  WAYS  AND  ETCHING  TIMES 


95 


nor  does  the  system  lend  itself  nearly  so  well  to 
accurate  logging  of  etching  dilutions  and  etching 
times.  Where  successes  are  gained  the  worker  has 
therefore  but  a vague  knowledge  of  how  he  can  repeat 
them.  Where  he  makes  a failure  he  is  even  more  in 
the  dark  about  the  stage  at  which  he  went  wrong. 

Yet,  what  is  one  man’s  poison  is  another  man’s 
meat.  It  is  said  that  the  finest  photographer  of 
Alpine  scenery  of  recent  times  made  his  best  negatives 
by  deliberately  contaminating  his  pyro  developer  with 
hypo.  We  all  must  choose  our  own  path. 

In  making  photogravure  plates  from  line  subjects, 
such  as  pen  or  pencil  drawings,  theoretically,  at  any 
rate,  resists  from  transparencies  wherein  the  middle 
tones  are  either  wholly  or  partially  absent  may  be 
etched  just  the  same  as  any  other  kind  of  resist. 
Actually  to  do  so  is  waste  of  time  and  attention. 

For  instance,  if  our  transparency  is  in  pure  black 
lines  upon  a clear  ground  (as  it  may  be  where  it  is  a 
copy  of  an  Indian  ink  original)  the  only  etching  bath 
required  will  be  one  which  gives  a rapid  and  sharp 
bite  to  the  copper  in  the  unprotected  parts  while 
allowing  no  action  whatever  where  the  gelatine - 
pigment  layer  is  of  even  a moderate  thickness.  The 
three  baths  either  of  which  should  suit  the  circum- 
stances almost  equally  well  are  40,  39  and  38.  Of  the 
three,  I have  found  39  and  38  preferable  because  they 
get  to  work  on  the  copper  most  promptly.  Etching 
time  for  a good  deep  etch  of  a line  subject  at  normal 
working  temperature  (70  to  75  deg.  Fahr.)  may  vary 
between  ten  and  twenty  minutes,  according  to  the 
grade  of  copper  to  be  acted  upon.  You  simply  pour 
on  the  bath  you  select,  rock  the  dish  gently  for  the 


96 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


time  you  favour,  take  out  the  plate  and  clean  it  for 
proofing.  When  doing  line  photogravure  a 175  line 
or  200  line  copy  screen  may  be  preferable  to  the 
standard  150  line  screen,  especially  for  small  fine  work. 
The  perfection  of  photogravure  reproduction  of  line 
subjects  is  unrivalled. 

When  we  come  to  making  plates  from  pencil 
drawings,  the  original  transparency  will  usually  not 
be  one  of  deep  black  lines,  but  will  have  at  least 
a little  half-tone  shading.  It  is  up  to  the  worker  to 
decide  how  many  changes  of  bath  strength  are  neces- 
sary to  do  justice  to  whatever  tonal  scale  there  may 
be.  For  average  pencil  sketch  reproduction,  where 
none  of  the  plate  is  required  to  be  deeply  etched,  the 
best  result  may  be  gained  by  starting  with  a short 
(two  or  three  minute)  etch  in  bath  38  and  going  on  to 
bath  37  for  the  final  seven  or  eight  minutes  of  etching 
time.  But  here,  as  always  in  the  technique  of  plate 
etching,  each  individual  worker  will  have  to  shoulder 
the  responsibility  of  finding  out  for  himself  what  bath 
strengths  and  etching  times  best  suit  his  own  dis- 
position and  ideas  of  what  he  wants.  As  his  plates 
provide  him  bit  by  bit  with  this  first-hand  information 
his  own  interest  is  to  record  it  clearly  and  simply,  so 
that  he  can  look  up  the  data  afterwards  whenever  in 
doubt. 

In  photogravure  plate  making  from  hand-drawn 
originals  I most  strongly  advise  that  the  first  described 
arrangement  of  a series  of  ready -prepared  and  standard- 
ised etching  bath  strengths  be  the  one  made  use  of,  and 
not  the  temptingly  simple  but  too  indefinite  dilution 
system  described  at  the  beginning  of  the  present 
chapter. 


CHAPTER  XV 


A short  theoretical  interpolation  to  make  plain  the 
fundamental  difference  between  a gravure  print  and 
a photo-mechanical  “ half-tone .”  This  chapter 

proves  gravure  to  be  as  truly  a continuous  tone 
printing  process  as  any  known  to  photography. 

In  my  introductory  chapter  I said  a little  about 
intaglio  copper  plate  printing.  I explained  briefly 
how  it  differed  from  typographic  printing.  Instead 
of  the  fatty  ink  being  impressed  upon  the  j)rinting 
paper  by  offset  from  projecting  portions  of  the  metal 
surface,  as  in  printing  from  type,  the  ink  wherewith 
the  picture  is  printed  from  an  intaglio  plate  lies  only 
in  the  plate’s  engraved  or  etched  hollows,  the  high 
metal  parts  having  been  previously  wiped  clean. 
The  same  plate  which  would  print  a positive  picture 
by  typographic  proofing  would  on  this  account  print 
a negative  picture  by  intaglio  proofing,  and  vice  versa. 

Also  I tried  to  show  how — unlike  a “ half-tone  ” 
photo -mechanical  newspaper  block  (fig.  24),  in  which 
there  are  no  real  half-tones  at  all,  but  only  an  illusion 
of  them  brought  about  by  the  microscopic  inter- 
mingling of  close -spaced  areas  of  dead  black  and  white — 
photogravure  plates  really  print  true  half-tones.  That 
is  to  say,  they  lay  a varying  thickness  of  ink  upon  the 
proofing  paper  for  shadow,  mid-tone  and  light-tone 
rendering,  just  as  with,  say,  a self -toning  or  a real 

97 


98 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


bromide  print  direct  off  the  negative.  For  there,  also, 
half-tones  are  made  by  a varying  thickness  of  reduced 
metallic  silver  held  in  the  paper’s  gelatine  coating 
(fig.  25). 

Admitted  that  a screen  photogravure  plate  has  all 
over  its  etched  portions  a network  of  high  copper  lines 
corresponding  to  the  lattice  of  the  screen  ruling,  these 


Fig.  24. — Half-tone  photo- mechanical  illustration  greatly  enlarged  to 
show  how  in  this  typographic  process  the  appearance  of  mid-tones 
is  an  illusion  produced  by  varying  size  of  black  dots  in  proportion 
to  their  white  surrounds.  All  dots  are  equally  black,  there  being 
no  real  variation  of  ink  depth.  Also  no  portion  of  the  printed 
area  is  entirely  white,  x 4. 

lines  hardly  vary  in  width  according  as  they  cross 
high  or  shadow  tones.  (Refer  back  to  fig.  3.)  Thus 
they,  of  themselves,  contribute  very  little  towards 
high-light  or  shadow.  If  they  do  contribute  at  all 
to  the  quality  of  printing  it  is  only  in  the  same  way 
that  a layer  of  fine  muslin  or  of  bolting  silk  between 
negative  and  sensitive  paper  will  contribute  to  “ break 


CAPABILITIES  OF  GRAVURE  UNEQUALLED  99 

up  the  surface  ” of  a photographic  print  and  broaden  its 
general  effect.  All  experienced  artistic  photographers 
know  of  that  dodge  for  rounding  up  and  creating 
“ atmosphere  55  in  a print  from  a hnnicky  or  spotty 


Fig.  25. — Micrograph  of  part  of  a photogravure  impression  on  paper 
showing  total  absence  of  dots  in  the  high-lights,  varying  depth  of 
ink  in  mid-tones  and  tendency  for  dots  to  run  together  and  so  make 
solid  shadows,  x 12  diameters. 

negative.  Well,  photogravure  performs  the  same 
service  without  loss  of  fine  detail.  Apart  from  it  the 
screen  does  nothing  more  than  fulfil  the  purely  mechani- 
cal function  of  preserving  intact  the  minute  array  of 
ink  troughs  from  which  our  printing  plate  derives  its 


100 


PHOTOGRAVURE  EOR  PHOTOGRAPHERS 


power  to  wipe  up  and  proof.  Any  plain  photographer 
will  understand  this  easily  enough.  Should  a half-tone 
worker  happen  to  set  eyes  on  it  he  will  the  more  readily 
understand  that  in  photogravure  the  first  thing  to  do  is 
to  forget  all  about  half-tone  screens  and  their  theory. 
Our  ideal  finished  printing  plate  is  a network  of  ink- 
pockets  each  surrounded  by  a thin  copper  wall  and  each 
pocket  of  a depth  corresponding  with  the  depth  of  tone 
of  the  transparency  image  from  which  the  plate  has 


Fig.  26.' — Micrograph  of  photogravure  plate  showing  portion  of  unetched 
margin  and  varying  depths  of  individual  ink  pockets  in  high-light, 
mid-tone,  and  shadow  regions.  The  original  showed  a network  of 
fine  tree  branches  against  the  sky.  x 15  diameters. 

been  made  (fig.  26).  As  the  pockets  vary  in  depth  so 
can  they  hold  more  or  less  depth  of  ink,  and  so  will 
more  or  less  depth  of  ink  in  due  time  be  transferred 
from  them  to  the  proofing  paper.  All  pigments  show 
strength  of  tone  according  to  the  depth  of  the  layer 
applied.  Hence  our  photogravure  proofs  will  be  built 
up  of  a genuinely  continuous  tone  structure  in  the 
accepted  photographic  sense  of  the  term.  Moreover, 
in  the  deepest  tones  of  all,  if  printing  depth  of  the 


REASON  OF  VELVETY  SHADOW  TONES 


101 


plate  is  correct,  and  if  printing  is  done  with  an  ink  of 
suitable  consistency  used  at  an  appropriate  tempera- 
ture, ink  dots  transferred  to  the  proofing  paper  from  the 
deeper  ink  pockets  will  run  together,  so  obliterating 
all,  or  almost  all,  trace  of  “ screen  pattern  ” or  the  wall 
network  between  them.  That  running  together  gives 
the  characteristic  velvety  quality  to  deep  shadows 
in  photogravure  which  can  be  matched  by  no  other 
direct  or  indirect  process. 


CHAPTER  XVI 


The  general  method  of  proofing  a gravure  plate.  Inks , 
papers  and  wiping  cloths  which  are  most  suitable. 
Getting  paper  into  condition.  The  relation  of  its 
hardness  to  soaking  time. 

Let  us  understand  just  what  we  have  got  to  do  for 
successful  plate  proofing.  Then  we  can  collect  our 
materials  and  attend  to  minor  details.  First  of  all 
the  plate  should  usually  be  warmed  to  the  point  where 
it  can  just  be  handled  in  comfort.  A small  amount  of 
copper  plate  ink  should  next  be  placed  upon  it  and 
gently  urged  into  the  hollows  by  light  dabbing  or 
rubbing  with  a gritless  flannel,  or  similar  rag  or  dabber. 
At  this  stage  the  whole  plate  becomes  one  smudge 
of  ink.  Now  take  a piece  of  sacking,  fold  it  into  a pad, 
warm  it,  and  rub  it  lightly  over  the  still  warm  plate’s 
surface,  giving  a polishing  motion  much  after  the  style 
of  cleaning  a brass  door  plate,  only  not  nearly  so  heavy 
or  energetic.  Then  take  a similar  pad  of  “ wiping 
cloth,”  which  is  a specially  coarse  kind  of  book  muslin, 
and  with  it  continue  the  wiping  until  the  surface  of  the 
plate,  where  unetched,  appears  once  again  free  of  ink 
(fig.  27).  By  this  time  the  etched  picture  should  stand 
out  clearly  as  an  ink  inlay  upon  the  copper. 

At  this  point  we  turn  to  the  printing  press.  A copper 
plate  press  (fig.  28  ) consists  of  a roller  arranged  to  lie 
upon  a flat  metal  bed-plate,  its  pressure  on  the 

]02 


ADJUSTING  A COPPER  PLATE  PRESS 


103 


bed-plate  being  controlled  by  set-screws  which  put 
force  upon  the  roller  shaft’s  bearings  at  either  end. 
By  tightening  down  the  set-screws  almost  but  not  quite 
as  far  as  they  can  be  made  to  turn  an  enormous  pressure 


Fig.  27. — Wiping  up  tlie  inked  plate. 


is  created  between  the  roller  and  the  bed.  The  arrange- 
ment, to  put  it  in  a nutshell,  is  a super-mangle  made  of 
cast  steel.  What  we  are  out  to  do  is  to  put  our  inked 
plate  and  damped  proofing  paper  through  the  mangle 
together,  so  adjusting  pressure  that  the  softened 
fibre  of  the  paper  shall  be  forced  into  the  plate  hollows 


104 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


far  enough  to  pick  out  the  ink  left  in  them  and 
take  it  upon  its  own  surface. 

To  ensure  this  happening  we  shall  have  to  soak  the 
paper  first  of  all  for  sufficiently  long  to  get  the 
harshness  out  of  it.  Also  we  may,  or  may  not,  need 


Fig.  28. — Semi-portable  double-geared  copper  plate  press.  The  damp- 
ing dish  for  paper  is  seen  on  its  left,  and  on  the  bench  in  the  fore- 
ground is  a simple  plate-heating  device  made  out  of  a piece  of 
stove  pipe  with  a small  bunsen  burner  inside  it. 


to  re-warm  the  printing  plate  so  as  once  more  to 
partially  liquefy  the  ink  it  is  holding.  And  again 
printing  pressure  must  be  sufficient,  yet  not  more  than 
sufficient,  though  in  photogravure  proofing  I have  found 
troubles  arising  through  over-pressure  to  be  slight  as 
compared  with  those  that  come  through  the  pressure 
on  the  roller  not  being  enough. 

You  need  not  necessarily  set  apart  a special  room 


ARRANGEMENT  OF  PROOFING  BENCH 


105 


for  plate  proofing,  but  I do  think  you  should  have  at 
least  one  good  long  and  fairly  deep  bench  kept  for  this 
only,  for  it  must  accommodate  the  following  : — Copper 
plate  press  (if  a small  bench  press  is  worked),  damping 
tray  and  brush  ; storage  box  for  damped  paper  ; 
sufficient  space  for  spreading  out  freshly-made  prints, 
and  some  kind  of  paper  and  card  cutter,  or  else  a* 
zinc  cutting  slab  for  cutting  printing  paper  to  size  and 
trimming  made  prints.  Next  to  this,  a separately 
compartmented-off  portion  of  the  bench  must  accommo- 
date the  supply  of  copper  plate  inks  ; a small  ink 
slab  ; a storage  box  for  dabbers  and  wiping  cloths  in 
use  ; some  kind  of  hot-plate  for  warming  plates  over, 
and  a whiting  box.  If  inks  are  to  be  compounded  by 
the  proofer,  he  will  also  need  shelves  or  equivalent  space 
for  copper  plate  oils  and  dry -powder  colours  as  well  as 
for  an  ink-grinding  stone.  Then  there  must  be  bottles 
of  paraffin  and  petrol  for  cleaning  the  ink  slab  and 
photogravure  plates.  Plates  which  are  valued  will 
need  to  be  stored  when  out  of  use  in  some  simple 
filing  cabinet.  My  own  (which  does  very  well)  is  a 
small,  empty  soap  box.  In  the  filing  box  each  plate 
is  kept  in  an  envelope  having  printed  on  the  front 
of  it  a pull  from  the  plate  itself. 

Some  place  or  other  will  also  be  necessary  for  storing 
a stock  of  printing  paper  and  card,  as  well  as  for  reserves 
of  wiping  cloths  and  similar  odds  and  ends  A cupboard 
underneath  the  work  bench  will  do,  or  even  curtained 
shelves  or  compartments. 

When  first  I mentioned  proofing  paper  I said  that 
any  kind  of  paper  or  thin  cardboard  could  be  used, 
and  this  is  true.  But  it  stands  to  reason  not  every  kind 
can  be  used  equally  simply,  nor  will  it  pick  up  ink 


106 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


from  the  plate  with  equal  readiness.  Since  the  readi- 
ness and  completeness  with  which  ink  is  transferred  to 
the  paper  decides  brilliance  of  tonal  scale  in  the  print, 
we  have  in  the  selection  of  our  proofing  papers  a valu- 
able way  of  exercising  control  over  the  prints  them- 
selves. The  rule  is  that  the  softer  the  texture  of  the 
paper  the  brighter  (more  contrasty)  will  be  the  print. 

The  softest  paper  I have  been  able  to  hit  upon  is 
ordinary  fluffless  blotting  paper,  such  as  the  well-known 
Ford  “ 428  Mill  ” brand.  On  it  I have  often  pulled 
successful  proofs,  where  the  plate  is  just  a trifle 
dull  in  what  should  be  bright  high -light  detail.  To 
prepare  blotting  paper  for  the  press  you  may  sprinkle 
it  generously  with  water,  stack  it  piece  upon  piece,  and 
leave  the  stacked-up  paper  under  the  gentle  pressure 
of  a sheet  of  plate-glass  for  sufficient  time  to  allow 
damp  permeating  all  the  pieces  of  paper  equally. 
Half  an  hour  or  so  should  do  this,  the  degree  of  damping 
to  aim  at  being  enough  to  make  the  paper  thoroughly 
limp,  but  stopping  short  of  leaving  it  streaked  with 
unabsorbed  surface  moisture.  This  is  the  regulation 
way  of  preparing  most  ordinary  copper  plate  papers  for 
the  press.  A simpler  and  far  quicker  method  with 
blotting  paper  is  simply  to  dip  it  into  a dish  of  water, 
lay  it  between  an  outer  cover  of  dry  blotting,  dab  off 
the  surface  moisture,  and  print  at  once,  the  whole 
time  of  paper  preparation  being  thereby  shortened  to 
something  under  half  a minute. 

Blotting  paper  is  not  a regularly  accepted  vehicle  for 
proofing  plates  upon.  The  regular  near  approach  to 
it  in  physical  properties  is  “ plate  paper,”  an  “ all-but  ” 
blotting  paper,  if  I make  myself  clear.  Plate  paper 
might  be  used  as  blotting  paper  if  you  took  care  not 


VARIOUS  PAPERS  AND  THEIR  BEHAVIOUR 


107 


to  let  it  smudge.  On  damping  for  the  printing  press 
it  absorbs  water  almost  as  rapidly  and  thoroughly  as 
true  blotting,  so  that  either  of  the  above-mentioned 
alternative  ways  of  damping  blotting  paper  will  do 
quite  well  for  plate  paper  also,  though  it  may  be  soaked 
overnight  without  resolving  itself  to  a mere  pulp. 
Plate  paper  is  the  brightest-printing  of  the  accepted 
copper  plate  and  photogravure  papers.  It  can  he 
had  in  light  weight,  medium  and  double  weight,  the 
double  weight  paper  being  as  stout  as  thin  cardboard. 

Proofing  paper  is,  as  far  as  my  unaided  observation 
goes,  a slightly  hot-pressed,  soft-textured  drawing 
paper.  It  is  the  best  of  the  comparatively  cheap-grade 
papers  for  photogravure  printing,  but  you  have  to 
leave  it  damped  overnight,  or  to  soak  it  in  water  for 
at  least  six  hours  before  use  Where  proofs  are  needed 
to  be  taken  quickly  on  it,  and  none  is  available  ready- 
damped,  it  may  be  prepared  in  a few  minutes  by 
soaking  in  warm  water  till  it  feels  fairly  limp,  then 
laying  it  down  upon  a clean,  flat  surface  and  brushing 
over  the  side  that  is  to  come  in  contact  with  the  printing 
plate  lightly  with  a soft  bristle  brush.  The  idea  is  to 
raise  a slight,  nap  on  the  surface  of  the  paper  which 
on  pressing  into  the  ink  pockets  of  the  plate  will 
send  down  fibrils,  and  so  help  entangle  and  lift  out 
the  ink. 

Next  in  order  of  their  facility  of  use  come  numerous 
soft -texture  drawing,  writing,  and  mounting  papers. 
In  general  they  need  from  one  to  three  days’  continuous 
soaking  in  water  to  get  them  into  a suitable  physical 
condition  for  proof  printing.  Last  of  all  come  the 
hard  writing  papers,  bond  pampers,  typing  paper,  and 
all  those  papers  having  a more  or  less  parchment-like 


108 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


texture  and  surface.  At  first  I met  with  such  uniform 
failure  in  attempts  to  get  passable  prints  on  them  that  I 
appealed  to  Mr.  Kimber  for  a list  of  the  sorts  of  paper 
which  were  usable.  He  told  me  definitely  that  any 
paper  at  all  was  usable  if  you  soaked  it  long  enough, 
but  added  that  the  practical  soaking-time  limit  was 
three  days,  for  by  the  fourth  day  paper  often  began 
to  go  stale  and  develop  patches  of  mould. 

As  three  days’  soaking  is  not  enough  for  a really  hard 
paper,  I solved  the  difficulty  by  adding  one -half  per 
cent,  of  formaldehyde  to  the  soaking  water  and  leaving 
the  paper  in  for  a week,  or  even  for  a fortnight.  In 
that  way  I found  I was  able  to  prepare  any  paper  I 
liked,  the  added  germicide  keeping  the  substance  of  it 
fresh. 

Coming  to  cardboard,  various  soft-textured  sheets  are 
on  the  market,  and  can  be  supplied  by  firms  catering  for 
copper  plate  printers.  Any  cardboard  can  be  prepared 
by  soaking,  provided  it  is  single  ; that  is,  not  of  the 
sort  which  splits  into  layers  when  kept  in  the  wet  state. 
If  so,  it  will  come  to  grief  in  going  through  the  printing 
press. 

Regular  plate  and  proofing  papers  can  be  bought 
in  white  and  also  in  “toned  ” (cream  or  buff)  surface. 
Bought  by  the  quire  (24  sheets),  plate  paper  of  the  best 
quality  costs  about  fivepence  a sheet  in  30  by  20  size, 
the  price  of  good  proofing  paper  in  the  same  size  being 
approximately  three -halfpence  a sheet. 

Next  we  come  to  inks.  I long  since  said  that  soft 
Bromoil  inks  will  do.  So  they  will,  and  very  nicely 
too.  I often  use  for  preference  those  made  by  Lecher- 
tier  & Barbe,  of  Jermyn  Street,  but,  compared  to  regu- 
lar copper  plate  ink,  they  are  very  expensive.  Kimber 


MAKING  COPPER  PLATE  INK 


109 


has  a series  of  soft  copper  plate  inks  ready  put  up  in 
1-lb..  I -lb.,  and  also  smaller  tubes.  Bought  in  this  way, 
they  cost  anything  from  6s.  to  15s.  a lb.  and  keep  in 
good  condition  indefinitely.  A couple  of  ounces 
of  ink  properly  used  will  ink  up  scores  of  6-in.  by  8-in 
proofs,  or  even  hundreds. 

Alternatively,  inks  can  be  made  by  the  worker  by 
grinding  dry  powder  colours  to  a very  stiff  paste 
with  burnt  oil,  working  powder  and  oil  together 
on  the  ink  slab  with  an  ink-grinding  stone,  a contraption 
shaped  rather  like  an  ancient  British  stone  hammer- 
head. Copper  plate  oils  I find  to  be  quoted  in  Penrose’s 
latest  list  at  something  under  one  guinea  a gallon, 
strong  copper  plate  oil  being  most  expensive  and  weak 
oil  least  expensive,  the  middle  oil  being  intermediate 
in  cost.  Copper  plate  oil  is  called  “ burnt  ” oil  because 
it  is  actually  caught  fire  to  in  process  of  making  it 
from  the  original  “ Baltic  ” linseed  oil.  The  burning 
distinguishes  it  from  litho  varnish,  which  is  formed 
from  raw  linseed  oil  without  being  made  to  flame. 

Using  strong  copper  plate  ink,  a plate  has  usually  to 
be  pretty  thoroughly  warmed  both  for  inking  and  for 
printing.  This  ink  is  made  up  with  strong  copper  plate 
oil.  Ink  made  with  weak  (thin)  copper  plate  oil  is 
called  “ dry-point  ink.”  Plates  can  be  inked,  wiped 
up,  and  printed  cold  with  dry-point  ink,  but  the  result 
is  flatter  and  not  so  rich.  Dry-point  ink  comes  in. 
very  handy  as  a means  of  getting  a quiet  print  from  a 
plate  slightly  over-contrasty  but  otherwise  satisfactory. 
So  here  we  have  yet  another  possible  line  of  control  in 
working  the  photogravure  process. 

I have  mentioned  that  sacking  may  be  used  for  inking 
the  plate,  and  also  for  a first  rough  wiping  cloth. 


no 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


The  most  suitable  kind  of  sacking  is  the  cheap  open- 
mesh  variety.  Also,  if  book  muslin  is  chosen  as  a 
second  wiping  cloth,  it  should  be  open-mesh  muslin 
rinsed  out  in  water  sufficiently  to  take  away  the  excess- 
ive first  stiffness,  but  not  washed  enough  to  make  it 
really  soft.  All  these  materials  are  used  dry,  of  course, 
except  for  the  ink  which  may  get  upon  them.  Wiping 
cloths  are  the  better  for  being  moderately  inky,  but 
each  worker  will  grow  his  own  preferences  about  the 
state  of  fattiness  in  which  he  prefers  to  use  them. 
As  for  the  plate-printer’s  hands,  they  get  inky  enough, 
whether  he  likes  it  or  not.  The  cheapest  wiping  cloths 
of  all  are  washed  meat  cloths.  In  practice,  wiping 
cloths  do  not  have  to  be  replaced  often  enough  to  call 
for  extreme  care  in  making  them  last  beyond  their 
appointed  time. 


CHAPTER  XVII 


Pulling  ‘ ‘ toned  ” and  “ natural  ” proofs.  How  to  keep 
them  clean,  with  some  concluding  remarks  upon 
flat  plates  for  the  benefit  of  original-minded  workers. 

You  have  soaked  your  paper,  and  selected  your  plate, 
and  you  intend  to  pull  a proof  from  it.  First  of  all 
put  on  a white  bibbed  apron.  It  is  important.  Warm 
the  plate  on  the  hot  plate.  My  earliest  hot  plate  was 
the  top  of  a tin  box  laid  on  a support  a little  way  above 
a small  bunsen  gas  flame.  The  easiest  way  of  getting 
ink  on  to  the  plate  in  the  first  place  is  to  squeeze  it 
out  of  a tube  in  little  dabs  over  the  etched  plate  while 
the  copper  heats.  Remove  the  plate  to  the  bench 
top,  select  a piece  of  sacking  or  flannel,  press  it  down  on 
the  hot  plate  till  warm  and  use  it,  as  already  directed, 
to  work  the  ink  gently  over  and  into  the  ink  pockets. 

Next,  wipe  up  the  plate  with  the  wiping  rags,  and  if 
you  want  to  pull  a “ toned  ” proof  all  that  remains  to  be 
done  is  to  polish  over  the  surface  of  the  plate  slightly  by 
gently  rubbing  with  the  flat  of  the  hand.  Then  take 
a clean  linen  duster  and  go  round  the  plate’s  edge  till 
all  vestage  of  ink  has  been  cleaned  from  here.  Other- 
wise the  line  of  the  plate  mark,  instead  of  being  simply 
a slight  depression  in  the  paper,  will  be  picked  out  by 
ink  smudge.  This  is  where  the  necessity  for  a bib  to 
your  working  apron  comes  in,  as  while  cleaning  round 
the  plate  edges  you  will  naturally  press  first  one  corner 

111 


112 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


and  then  another  against  yourself.  Denison  recom- 
mends damp  chamois  leather  for  plate  edge  wiping. 

A “ toned  55  print  is  one  whereon  the  high -lights 
as  well  as  the  rest  of  the  picture  have  a slight  trace  of 
“ tone,”  or  degradation,  from  residual  ink.  Many 
artistic  people  prefer  proofs  this  way.  Others,  includ- 
ing myself,  make  for  a “ natural  ” proof,  wherein  the 
highest  light  is  truly  white,  or  inkless.  To  get  it, 
instead  of  finally  preparing  the  plate  for  the  press  by 
a simple  light  rub  over  with  the  plain  hand,  you  first 
of  all  rub  a very  little  double -washed  whiting  into 
the  skin,  so  as  to  reinforce  its  power  as  a natural 
polishing  pad.  With  practice  you  soon  get  to  learn 
just  how  much  whiting  and  how  much  of  the  polishing 
action  upon  the  copper  surface  is  enough  to  clean  the 
high-lights  of  a plate  completely,  without  either  taking 
too  much  ink  away  or  clogging  the  half-tones.  If  the 
plate  is  to  be  printed  warm  it  has  possibly  to  be  returned 
to  the  hot  plate  for  a few  moments  after  wiping  up. 
Then  it  should  be  laid  squarely  upon  the  bed  of  the 
printing  press  and  the  damped  paper  should  be  picked 
up  and  laid  upon  it,  using  a “ clip  ” made  by  folding  a 
slip  of  notepaper  over  in  the  middle  (fig.  29).  (Don’t 
forget  already  your  hands  are  very  inky. ) Take  care  to 
place  the  paper  squarely  in  position  upon  the  copper. 

You  may  shift  the  paper  upon  the  plate  gently,  if 
you  like,  after  laying  it  down  and  before  putting  on 
pressure  from  the  roller.  That  will  not  cause  smudging, 
for  the  part  of  the  copper  so  far  in  contact  with  the 
paper  is  only  its  uninked  upper  surface.  Now  cover 
paper  and  plate  with  a clean  paper  backing,  next  with 
the  felt  *c  fronting,”  then  with  the  blanket,  or  blankets, 
and  turn  the  roller  evenly  and  with  a steady  hand  so 


HINTS  ON  PROOF  PTTLLTNG 


113 


that  a proof  is  taken.  The  plate  may  he  run  once 
through,  or  forth  and  back  again.  If  pressure  is  not 
sufficient  to  make  an  even  impression  with  the  single 
passage  under  the  roller  it  should  be  increased. 

As  you  lift  up  the  printed  proof  you  get  sight  at 
last  of  the  full  result  of  your  labours  (fig.  30). 

Set  the  proof  to  dry,  and  in  a day  or  two’s  time,  if 
you  wish  to  flatten  out  the  plate  mark  somewhat, 


Fig.  29. — A clip  made  of  a small  doubled-over  piece  of  dry  paper,  being 
used  to  pick  up  the  proof  to  preserve  it  from  contact  with  ink- 
smeared  fingers. 


you  can  do  so  by  passing  the  dry  print  by  itself  through 
the  press,  laying  it  simply  on  the  clean  bed-plate, 
face  downwards,  with,  of  course,  the  blankets  over  it. 

Make  certain  to  keep  the  bed-plate  of  the  press 
always  scrupulously  clean  by  wiping  it  over  frequently 
with  a linen  rag  slightly  moistened  at  one  part  with 
whiting  and  water. 

Total  time  for  inking  and  wiping  up  a plate  and 
proofing  it  may  be  five  minutes. 


114 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


This  completes  a simple  and  very  elementary 
description  of  copper  plate  printing  from  home-made 
photogravure  plates  by  the  rag  wiping  method.  Need- 
less to  say,  it  by  no  means  exhausts^the  possibilities 


Fig.  30. — The  final  moment.  First  sight  of  a first  impression. 

of  simplified  photogravure.  For  instance  there  is  a 
wide  field  for  exploration  in  the  direction  of  adapting 
“ doctor  ” wiping  to  the  flat  photogravure  plate,  as 
has  already  been  successfully  done  in  rotary  photo- 
gravure (see  the  next  chapter),  thereby  making 
possible  the  wonderful  recent  speeding  up  in  printing 
fine  photogravure  magazine  illustrations.  In  this 
latter  direction  I have  so  far  tried  only  a few  none  too 


ROOM  FOR  FURTHER  EXPERIMENT 


115 


successful  experiments,  but,  probably  as  a measure  of 
ignorance,  my  hopes  remain  high.  At  least,  I believe 
that  if  not  myself,  then  some  other  direct  photographic 
worker  has  a good  chance  of  simplifying  and  speeding 
flat  plate  proofing  in  the  near  future  by  adapting  to 
“ amateur  ” flat  bed  work  some  at  least  of  the  newer 
refinements  of  the  rotary  “ cylinder  ” process. 

Whether  this  would  mean  improving  quality  of 
our  proofs  as  well  as  quickening  their  production 
remains  to  be  seen.  The  process,  as  I have  en- 
deavoured to  present  it  to  my  readers  in  the  fore- 
going chapters,  has  given  me  so  much  real  delight 
that  I cannot  believe  it  will  leave  everyone  else  quite 
cold  if  once  they  can  be  persuaded  to  give  it  a fair 
trial. 

For  those  whose  interest  is  rather  with  rapid  pro- 
duction methods  than  with  leisurely  flat  plate  printing 
I have  appended  the  chapter  which  follows,  while 
hastening  to  add  that  it  aims  no  higher  than  to  give 
the  briefest  of  working  outlines  of  rotary  gravure. 


CHAPTER  XVIII 


Elements  of  Rotary  Gravure 

Though  photogravure  worked  along  the  lines  laid 
down  in  previous  chapters  is  capable  of  giving  beauti- 
ful monochrome  prints  which  compare  in  quality 
with  good  photographs,  the  speed  with  which  they 
can  be  pulled  in  a copper  plate  press  is  extremely 
slow  as  judged  by  standards  of  typographic  printing. 
A jobbing  printer  working  with  a treadle-operated 
machine  can  turn  out  cheap  circulars  (of  the  kind  that 
ill -dressed  gentlemen  hand  to  you  as  you  pass  along 
the  street)  at  a speed  of  over  one  thousand  an  hour. 
Large  rotary  newspaper  presses  print  at  rates  exceed- 
ing twenty  thousand  an  hour.  In  contrast  to  this  it  is 
a smart  worker  who  single-handed  can  turn  out  in 
one  hour  many  more  than  a dozen  really  nice  “ natural  ” 
gravure  proofs  from  a moderate  sized  (say,  seven  by 
five  inch)  flat  plate,  rag-wiped  and  printed  in  a copper 
plate  press.  Obviously,  then,  plate  photogravure  which 
may  be  excellent  from  the  point  of  view  of  a photo- 
grapher does  not  fill  the  needs  of  the  general  printing 
trade.  To  make  it  do  so  the  process  must  be  so 
modified  as  greatly  to  speed  it  up. 

Long  since,  a similar  speeding  up  in  typographic 
printing  was  effected  by  stereotyping  the  original 
type  forms,  bending  the  stereotype  plates  so  that  they 
could  be  snugly  fastened  round  a cylinder  and  causing 

116 


THE  “ DOCTOR  ” THE  SECRET  OF  ROTOGRAVURE  117 

the  cylinder  with  its  typographic  facing  to  revolve 
quickly.  The  cylinder  rim  was  made  to  come  into 
contact  with  inking  rollers  and  then  to  press  against 
paper  fed  through  the  printing  machine  from  a con- 
tinuous roll.  In  this  way  modern  rapid  newspaper 
and  magazine  printing,  up  to  speeds  well  into  the 
tens  of  thousands  an  hour,  became  possible.  The 
problem  for  the  rapid  photogravure  printer  was  to 
adapt  his  intaglio  process  similarly  to  working  from  a 
cylinder  kept  continuously  inked  and  revolved. 

Introduction  of  the  photogravure  “ copy  screen,” 
described  in  an  earlier  part  of  this  book,  solved  one 
great  initial  difficulty.  To  fashion  a cylinder  from 
pure  electrolytic  copper,  or  alternatively  to  turn  an 
accurate  cylinder  from  mild  steel  and  deposit  copper 
electrolyfcically  upon  its  face  to  sufficient  depth  to 
allow  of  subsequent  etching,  was  again  quite  feasible. 
Added  to  this  it  was  found  that  a screen  photogravure 
resist  could  almost  as  easity  be  got  down  upon,  and 
developed  upon,  a curved  as  upon  a flat  copper  sur- 
face. It  meant  no  more  than  detail  modifications  in 
the  shape  of  troughs  for  hot  water,  spirit  and  water 
and  etching  solution.  When  it  came  to  actual  print- 
ing, the  developed  copper  cylinder  could  be  inked 
over  its  surface  with  ink  rollers  and  the  paper  could 
be  fed  against  it.  But  what  about  wiping  it  up  ? 

Early  attempts  with  greasy  ink  and  modified  rag 
wiping  by  rotary  pads  soon  showed  that  the  process 
as  worked  out  for  flat  plates  broke  down  at  this  point. 
However,  the  situation  was  saved,  and  rapid  rotary 
gravure  made  definitely  commercial,  by  the  introduc- 
tion of  what  is  known  as  “ doctor  wiping.” 

Doctor  Wiping. — A rotary  gravure  “ doctor  blade  ” 


118 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


is  a flat  and  flexible  piece  of  steel  tempered  to  a yellow- 
brown  temper  and  as  a general  rule  approximately  two 
inches  wide.  Its  length  must  be  rather  greater  than 
that  of  the  engraved  cylinder  to  which  it  will  minister, 
while  its  thickness  may  vary  between  the  one  hundred 
and  fiftieth  and  the  fiftieth  part  of  an  inch.  One 
side  of  the  doctor  is  clamped  firmly  in  a “ carriage  ” 


Fig.  31. — Angle  of  inclination  of  the  doctor  to  the  printing  cylinder. 
The  cylinder  rotates  clockwise  as  shown  in  this  diagram. 


or  holder,  while  the  free,  or  “ wiping,”  edge  is  caused 
to  press  upon  the  printing  cylinder  at  a slight  angle. 
This  wiping  edge  of  the  doctor  blade  has  to  be  pre- 
pared for  its  work  by  bevelling  it  with  a fine  instrument - 
sharpening  stone,  as  though  it  were  a miniature  chisel, 
and  finally  just  blunting  the  edge  of  the  bevel  to  pre- 
vent it  scratching  the  copper  upon  which  it  will  press. 
Diagram  fig.  31  shows  relative  position  and  usual 
angle  of  inclination  of  the  doctor  to  the  printing 
cylinder.  Bear  in  mind  : — 


RULES  FOR  DOCTOR  BLADE  SETTING 


119 


{a)  The  thinner  a doctor  blade  the  more  ink  will 
it  remove  from  the  ink  pockets  forming  the  photo- 
gravure printing  surface.  Hence  the  lighter  will 
printed  impressions  be. 

(b)  The  thicker  the  ink  used  in  the  machine  the  less 
must  be  the  doctor’s  angle  of  slope  out  of  normal  to 
the  printing  cylinder  radius.  Usually  a slope  of  the 
doctor  blade  amounting  to  somewhere  between  ten 
and  twenty  degrees  gives  satisfactory  all-round  results. 
As  the  doctor  wipes  the  cylinder  it  is  given  a certain 
amount  of  sideways  travel.  Without  this  the  printing 
surface  would  soon  be  scored  with  fine  scratches. 

A simple  way  of  envisaging  the  function  of  the 
doctor  on  a rotary  gravure  machine  is  to  think  of  it 
as  a thin  metallic  squeegee. 

Now  to  the  ink.  Anyone  who  has  experience  of 
the  stiff  jelly-like  consistency  of  copper  plate  (burnt 
oil)  ink  used  for  rag  wiping  upon  flat  plates  will  not 
need  to  be  told  that  no  mere  squeegeeing  would  clean 
this  off  an  intaglio  surface  well  enough  to  make  possible 
“ natural  ” printing,  or  in  fact  any  sort  of  passable 
gravure  printing  at  all.  Ink  used  in  rotary  work  is 
entirely  different  and  known  as  either  ££  water  ” or 
££  spirit  ” ink. 

Rotary  Gravure  Ink. — Spirit  ink  gives  by  far  the 
best  impressions,  so  we  will  consider  it  first.  As 
supplied  by  gravure  ink  makers  it  pours  out  easily 
from  its  container,  being  of  the  consistency  of  the  raw 
cream  served  for  adding  to  tea  instead  of  milk. 
Without  attempting  to  divulge  the  secret  of  its  manu- 
facture we  should  know  it  contains  finely  ground 
powder  colour  mixed  with  a varnish  binder,  the  whole 
being  held  in  a thin  volatile  liquid  which  may  be 


120 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


mineral  naphtha,  xylol  or  even  turpentine  according 
to  the  quality  of  the  ink  and  rapidity  with  which  it  is 
required  to  dry  on  the  printing  paper.  Usually, 
gelatine  or  glue  rollers  are  arranged  on  the  printing 
machine  to  pick  the  ink  out  of  its  ink  well  and  apply 
it  to  the  printing  cylinder  with  sufficient  pressure  and 


Fig.  32. — Doctor  blade. 


thoroughness  to  force  the  thin  ink  down  into  the 
etched  ink  pockets.  At  the  same  time  it  goes,  of 
course,  promiscuously  over  the  whole  copper  surface. 
The  ink-smeared  copper  cylinder  face  now  passes  up 
against  the  doctor  blade  which  removes  the  whole  of 
the  ink  from  its  unetched  portions  and  causes  it  to 
drip  back  into  the  ink  well  again.  The  “ doctored  ” 
printing  cylinder  face  can  now  be  fed  with  gravure 
paper  or  card,  either  in  separate  sheets,  by  hand 


IMPRESSION  CYLINDER  AND  PAPER 


121 


feeding,  or  continuously,  by  reel  feeding,  and  the 
paper  duly  impressed  with  the  contents  of  the  still- 
charged  ink  pockets. 

To  get  enough  pressure  between  paper  and  copper 
a second  cylinder  called  the  impression  cylinder, 
faced  with  a hard  smooth  rubber  or  similar  surface, 
is  caused  to  bear  upon  the  back  of  the  paper  with 
considerable  pressure,  though  not  with  nearly  as 
intense  a pressure  as  is  required  when  pulling  a similar 
sized  rag-wiped  proof  in  a copper  plate  hand  press. 
Why  ? The  reason  lies  partly  in  the  comparative 
thinness  of  rotary  gravure  ink.  It  is  so  thin  that  a 
suitable  paper  need  not  be  damped  for  it  to  give  a 
full  impression. 

Paper. — That  implies  a special  grade  of  paper  for 
rotary  gravure  printing.  And  so  there  is  regular 
“ gravure  paper.”  Several  big  British  and  Continental 
makers  supply  it  in  various  weights.  I have  been 
getting  what  gravure  paper  I need  from  the  firm  of 
John  Dickinson  & Son,  Ltd.,  65,  Old  Bailey,  London, 
E.C.  Usually  orders  are  given  in  minimum  lots  of 
one  ton,  but  paper  makers,  like  drapers,  have  their 
remnants,  though  the  name  for  them  in  the  paper 
making  industry  is  “remainders.”  And  so  one  can 
generally  get  a few  reams  when  no  more  than  this  is 
required.  Typical  cheap  gravure  paper  has  a smooth 
shiny  surface  but  takes  pen  and  ink  more  hke  blotting 
than  ordinary  paper.  None  the  less,  practically  any 
paper  can  be  printed  by  rotary  gravure  if  pressure  of 
the  impression  cylinder  and  ink  consistency  are 
carefully  enough  regulated. 

Water  ink  for  gravure  is  rather  hke  a thin  distemper 


i 


122 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


colour.  Dutch  seedmen’s  catalogues  are  generally 
printed  in  water  ink.  You  know  it  from  spirit  ink 
by  the  simple  test  of  moistening  a finger  tip  and 
rubbing  it  over  the  printed  impression.  If  it  smears, 
a water  ink  has  been  used.  If  not,  it  is  spirit  ink 
printing. 

Printing  speed  of  rotary  gravure  may  vary  between 
five  hundred  and  six  thousand  an  hour  for  spirit  ink, 
according  to  the  machine.  Water  ink  printing  speeds 
are  said  to  be  prodigious,  up  to,  and  even  over,  ten 
thousand  an  hour,  but  on  the  latter  point  I am  merely 
repeating  hearsay. 

The  Method  ih  Brief. — Now  that  some  main  out- 
standing points  of  difference  between  the  technique 
of  hand-printed  and  rotary  gravure  have  been  ex- 
plained, it  may  be  helpful  to  run  rapidly  over  the 
method  of  preparing  and  printing  from  a “ cylinder,” 
or  rotary  gravure,  resist. 

First  steps,  up  to  the  point  of  squeegeeing  the 
printed  and  screened  gravure  tissue  on  to  the  copper, 
are  precisely  as  with  flafc  plate  gravure,  described  in 
preceding  chapters.  So  in  general  is  the  method  of 
cleaning  the  copper  cylinder  surface.  It  should  be 
scrubbed  with  whiting -ammonia  paste  till  bright  and 
grease-free.  Getting  the  wetted  tissue  into  contact 
with  the  metal  presents  only  those  physical  complica- 
tions arising  from  the  cylinder’s  far  greater  bulk  and 
circular  shape.  There  is  no  good  reason  why  a cylinder 
should  not  be  bodily  immersed  in  a twenty-five  per 
cent,  solution  of  methylated  spirit  and  water,  and  the 
tissue  be  got  into  position  under  the  surface  of  the 
liquid.  Still,  as  this  means  frequent  renewal  of  con- 


ETCHING  A “ CYLINDER  ” 123 

siderable  quantities  of  spirit  solution,  a more  general, 
and  almost  equally  effective,  way  of  going  to  work 
is  to  support  the  cylinder  between  uprights,  place  a 
large  dish  beneath  it,  pour  the  spirit  and  water  over 
the  cylinder  and  rapidly  put  the  tissue  in  position 
before  the  liquid  has  time  wholly  to  drain  away, 
squeegeeing  at  once  for  good  contact  between  the 
two.  This  makes  it  easy  to  get  several  printed  tissues 
into  place  one  by  one,  where,  as  often  happens,  a 
cylinder  is  required  to  print  more  than  one  subject 
at  a time.  Making  up  the  positives  to  print  together 
in  one  frame  on  to  a single  piece  of  gravure  tissue  is 
an  even  better  alternative  where  applicable. 

Development  presents  again  only  the  simple  problem 
of  providing  a sufficiently  large  tank  the  water  within 
which  can  be  kept  at  correct  developing  temperature 
while  the  cylinder  is  immersed.  Drying  the  developed 
resist  calls  for  some  way  of  slowly  rotating  the  cylinder 
while  warm  air  is  blown  upon  it  by  a fan.  Hand 
rotation  is  quite  good  enough. 

Having  dried  the  developed  cylinder,  the  next  thing 
is  to  coat  all  uncovered  copper  and  also  any  part  of 
the  cylinder  which  may  come  into  contact  with  etch- 
ing solution  with  a good  liberal  coat  of  acid  resist 
varnish.  Ordinary  acid  resist  varnish  is  a solution  of 
shellac  in  methylated  spirit.  Penrose  also  supplies  a 
varnish  called  by  the  trade  name  “Mogul.”  I have 
found  it  far  better.  One  great  point  of  advantage  is 
that  it  has  a brown  colour,  so  that  it  is  impossible  to 
omit  to  coat  any  part  of  the  cylinder  without  seeing 
that  the  metal  remains  bare.  Mogul  varnish  does  not 
“ shift,”  which  means  it  does  not  run  unduly  while 
setting.  Its  drying  is  very  quick  and  thorough. 


124 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


The  solvent  used  appears  to  be  benzine.  For  ruling 
margin  boundary  lines  this  varnish  may  be  stood 
in  a saucer  until  it  thickens  up  sufficiently  through 
evaporation.  An  alternative  is  to  rule  lines  with 
gravure  spirit  ink  thinned  down  with  benzine  or 
xylol.  In  summer  time  a little  turpentine  will  help 
the  mixture  not  to  dry  unduly  while  in  the  ruling 
pen. 

Cylinder  Development. — Development  of  a 
gravure  cylinder  is  most  simply  done  by  having  the 
etching  solution  contained  in  a shallow  trough  the 
curvature  of  which  is  that  of  a portion  of  a circle  of 
somewhat  greater  radius  than  the  cylinder’s  own. 
Stand  the  trough  so  that  the  horizontally  supported 
cylinder  dips  comfortably  into  it.  Usually  it  will  be 
necessary  to  provide  some  means  of  keeping  the  con- 
tents of  the  trough  up  to  (but  never  above)  etching 
temperature.  At  an  earlier  portion  of  this  book  I 
said  the  system  of  using  separate  baths  of  varying 
gravity,  and  replacing  one  by  another,  was  the  surest 
and  best.  So  it  is  for  a flat  plate  worker  or  a beginner. 
In  cylinder  etching,  however,  once  some  experience 
has  been  gained,  the  physical  aspect  of  the  problem 
enters  in  sufficiently  to  put  the  balance  in  favour  of 
gravity  alteration  by  dilution.  Starting  with  41 
Beaunffi,  or  more  usually  40  Beaume  perchloride 
strength,  the  bath  may  be  diluted  by  addition  of 
plain  water  (at  etching  temperature)  in  proportion  of 
two  to  four  fluid  drams  to  each  pint  of  original  etching 
fluid,  repeating  this  at  intervals  of,  perhaps,  a 
couple  of  minutes  (all  according  to  circumstances) 
until  the  gravure  resist  has  been  just  penetrated  to  the 
high-lights.  Binsing  and  cleaning  are  sufficiently 


TYPES  OF  CYLINDERS 


125 


explained  in  the  part  of  the  book  dealing  with  flat 
gravure  plates. 

Next,  the  cylinder  has  to  be  put  in  position  on  the 
machine,  the  ink  duct  filled,  and  paper  fed.  Details 
of  machine  minding  vary  with  whatever  pattern  is  in 
use,  but  the  reader  has  by  now  a general  idea  of  how 
to  get  to  work.  The  rest  he  must  fill  in  for  himself 
through  actual  experience. 


Fig.  33. — Cylinder. 

Types  of  Cylinders. — Four  types  of  gravure 
printing  cylinder  come  to  mind.  The  simplest,  and 
I suppose  clumsiest,  is  a solid  steel  cylinder,  integral 
with  its  shaft  and  gear  drive.  Upon  its  surface  has 
been  deposited  a sufficient  thickness  of  electrolytic 
copper  to  allow  of  etching  depth.  When  you  want  to 
etch  this  cylinder  it  has  to  be  removed  as  a whole,  a 
heavy  task  considering  the  cylinder’s  weight,  and  one 
often  calling  for  several  helpers  as  well  as  for  the  aid 
of  block  and  tackle. 

The  next,  and  very  usual  type  of  cylinder,  is  one 
wdiere  the  shaft  and  gear  wheel  are  permanently 


126 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


attached  to  a slightly  coned  mandrel.  Over  this 
mandrel  fits  a mild  steel  sleeve.  The  copper  is  carried 
as  a deposit  upon  this  sleeve’s  surface. 

In  the  third  type  of  cylinder  the  gear,  pinion  and 
mandrel  are  retained,  but  the  sleeve,  instead  of  being 
formed  of  copper  deposited  upon  a steel  or  iron  base, 
is  made  of  thick  copper  throughout.  Before  going 
on  to  describe  the  last  and  latest  type  of  printing 
cylinder  let  me  say  wherein  the  much  thicker  copper 
sleeve  scores.  It  is  in  this  wise  : — 

When  you  have  printed  all  the  copies  you  want  of 
whatever  subjects  are  etched  upon  the  cylinder  copper, 
and  wish  to  use  the  same  cylinder  face,  or  sleeve, 
over  again,  you  have  to  put  it  in  a lathe,  or  preferably 
in  a special  grinder,  grind  off  enough  metal  to  cut 
away  the  etched  image,  and  repolish,  as  far  as  necessary, 
by  buffing  with  emery  or  tripoli  polishing  compound. 
Having  done  this  you  can  use  the  cylinder  as  a fresh 
blank,  but,  of  course,  your  former  etching  has  had  to 
be  scrapped.  To  print  another  edition  of  any  of  the 
old  gravure  pictures  you  would  have  to  put  down  a 
new  resist,  etch  again  and  hope  that  the  fresh  attempt 
comes  out  sufficiently  like  the  last  one  for  your 
customers  not  to  notice  the  difference.  Except  for 
this  last-named  drawback  the  more  often  you  can 
re -grind  and  polish  a cylinder  face  and  re-use  it  the 
less  need  be  charged  to  cost  of  copper  in  pricing 
gravure  work.  There  are  other  reasons  why  a good 
thick  copper  cylinder  sleeve  is  likely  to  give  all-round 
better  service  than  a skimpy  deposit  on  steel.  But 
we  shall  also  realise  something  else,  and  that  quite 
clearly.  If  it  were  possible  to  remove  the  etched 
surface  intact  from  a gravure  cylinder  after  the  con- 


RECENT  ADVANCE  IN  CYLINDER  DESIGN  127 


elusion  of  printing  a first  edition  (like  skinning  the 
outer  coat  from  an  onion)  and  keep  this  etched  skin  for 
re-use  in  printing  subsequent  editions,  it  would  be 
simpler  technique  and  better  business  both  arrived 
at  together.  That  brings  us  to  the  fourth  type  of 
gravure  printing  cylinder,  a wholly  modern  intro- 
duction, hardly  yet  arrived  at  commercial  perfection, 
whereby  the  attempt  is  made  to  avoid  having  to 
destroy  old  work  by  re -grinding  before  putting  on 
new. 

.The  fourth  type  of  printing  cylinder  carries  no 
permanent  deposit  of  copper.  Nor  does  it  take  a 
substantial  copper  sleeve.  Instead  of  this,  a thin 
polished  copper  sheet  is  stretched  tightly  round  the 
mandrel  and  bolted  down  to  give  as  unshifting  a 
printing  surface  as  possible.  If  thin  and  flexible 
enough,  the  copper  sheet  may  be  etched  exactly  as 
might  be  a flat  plate.  If  less  thin  it  should  first  be 
shaped  by  fitting  on  to  a dummy  cylinder,  etched 
and  removed  to  the  printing  cylinder.  Or  it  may  be 
bolted  to  the  printing  cylinder  itself  and  etched  while 
fastened  in  place.  In  etching  such  sheet  copper 
gravure  printing  surfaces,  bear  in  mind  to  give  the 
back  of  the  sheet  a coat  of  protective  varnish  before 
etching.  Also  equally  bear  in  mind  to  clean  off  this 
protective  coat  if,  and  when,  the  sheet  is  removed 
from  its  dummy  etching  cylinder  to  the  real  printing 
cylinder.  Most  important  of  all,  remember  that  the 
smallest  speck  of  grit  caught  between  the  back  of  the 
sheet  and  its  printing  support  will  force  up  the  copper 
and  give  rise  to  a metallic  island  surrounded  by  an 
ink-filled  trough  which  the  doctor  cannot  wipe  clean 
when  you  come  to  start  printing.  After  an  edition 


128 


PHOTOGRAVURE  FOR  PHOTOGRAPHERS 


is  printed,  the  thin  sheet  metal  can  be  taken  off  its 
mandrel,  cleaned  with  benzine  or  turps,  perhaps 
waxed  to  protect  its  face,  and  stored  for  second  edition 
printing  without  thereby  locking  up  any  considerable 
amount  of  capital.  In  proportion  as  this  rotary  sheet 
gravure  becomes  improved  so  will  intaglio  printing  be 


Fig.  34. — Small  gravure  machine. 

(Pickup  & Knowles). 

A Impression  cylinder  ; B Copper  cylinder  ; C Doctor. 

more  and  more  able  to  stand  up  in  competition  with 
offset  lithography  which,  at  the  moment,  is,  I dare 
say,  its  nearest  (though  far  inferior)  technical  and 
commercial  competitor. 

Just  a Hint  oh  Colour  Gravure. — I have  not 
seriously  touched  it  myself,  though  I have  had  a 
good  deal  of  experience  of  three-colour  work  in  what 
is  usually  called  direct  photography.  From  results 


TO  WISH  ALL  READERS  SUCCESS 


129 


seen,  I do  not  hesitate  to  name  rotary  gravure  as  the 
best  all-round  solution  of  two-and  three-colour  photo- 
printing. Flat  plate  gravure  is  put  out  of  the  running, 
it  seems  to  me,  by  the  necessity  to  soak  the  paper 
before  taking  an  impression.  Not  only  does  that 
introduce  serious  trouble  from  expansion  and  con- 
traction, but,  still  worse,  in  flat  plate  work  the  capacity 
of  the  paper  to  pick  up  copper  plate  ink  becomes  so 
much  diminished  after  its  first  pull  through  the  press 
as  to  make  accurate  colour  regulation  impossible. 
(I  have  done  enough  to  find  that  out. ) 

In  printing  rotary  gravure  you  can  use  a good 
quality  thin  smooth  ivory  card,  and  use  it  dry.  So 
you  have  a printing  surface  which  remains  the  same 
both  in  size  and  ink-taking  capacity  as  between 
colour  impression  and  colour  impression.  That  way 
lies  hope. 


THE  LONDON  AND  NORWICH  PRESS,  LIMITED,  ST.  GILES’  WORKS,  NORWICH 


I 


ADVERTISEMENTS 


Autotype 

Photogravure  Tissues 

Recognised  as  the  most  regular  and  perfect 
material  manufactured  for  the  process,  and  used 
by  the  principal  houses  at  home  and  abroad. 


The  Company’s  practical  knowledge  of  the 
process  is  placed  at  the  disposal  of  their  clients. 
Samples  and  list  free  upon  Application. 

Carbon  Positives  for 
Photogravure  Work 

These  have  every  advantage  over  dry  plates. 
They  give  a longer  scale  of  gradation,  better 
quality,  and  reduce  cost  by  50  to  75  per  cent. 


Autotype  Collodions,  Photo-Litho  Transfer 
Papers,  etc. 


THE 

AUTOTYPE  COMPANY  Ltd 

59,  NEW  OXFORD  STREET 
LONDON,  W.C.  1 


Works 

WEST  EALING. 


32  Prize  Medals  and  Diplomas 
Grand  Prix,  Turin. 


ADVERTISEMENTS 


11 


INKS  FOR 
PHOTOGRAVURE 


Any  shade  of  ink  supplied  for  this 
process. 

Gloss  Inks  and  Matt  Inks  as  may 
be  required. 

Special  shades  of  Tri-Chromatic 
Inks  for  Photogravure. 

Inks  specially  adapted  for  sheet  fed 
or  High-speed  Rotary  Machines. 

Best  quality  Flat  White  Medium 
and  Gloss  White  Medium  for 
reducing  shades. 

Xylol  of  the  highest  grade  and 
perfect  drying  qualities. 


31  - 34, 

CURSITOR  ST., 
CHANCERY  LANE,  LONDON,  E.C.  4. 


Ill 


AD  VERTISEME  NTS 


“THE  HOUSE” 

FOR 

Photo-Engraving  Supplies 

Everything'  required  for 
Photogravure,  Photo-Litho- 
graphy, Half-Tone,  or  Line 
Blocks,  in  Black  and  White 
or  Colour. 

We  were  Pioneers  in  the 
Production  of  Machinery 
and  Supplies  for  Machine 
Printed  Photogravure  and 
the  Experience  of  Thirty 
Years  is  at  your  Service. 

A.  W.  Penrose  & Co.,  Ltd. 

109,  FARRINGDON  ROAD, 
LONDON,  E.G.  1. 


ADVERTISEMENTS 


IV 


COPPER  PLATE  PRESSES 

33  Different  Styles  to  select  from. 

PRICES  - - £5  to  £220. 

SECOND-HAND  PRESSES  ALWAYS  IN  STOCK. 


With  Rollers  12'  long  and  iron  plank  24  x 12"  - £17  0 0 

„ 16"  „ „ 30  x 16"  - £22  10  0 

„ £0"  „ „ 35  x 20"  - £29  0 0 

ALL  TOOLS  AND  MATERIALS  FOR  PHOTOGRAVURE, 
ETCHING,  ENGRAVING,  Etc. 

Copper  and  Zinc  Plates,  Points,  R.W.S.  Water  Colour  Paper  and 
Scrapers,  Burnishers,  Grounds,  all  Artists’  Materials. 

Mordants,  Colours,  Inks,  and  

Hand-made,  Dutch,  India,  48  page  Illustrated  Catalogue, 
Japanese  and  Plate  Papers.  post  free,  on  request. 

WILFRED  C.  KIMBER, 

Tankerton  Street  Works,  Cromer  Street,  London,  W.C.  1 

(Near  King’s  Cross  Stations.) 

Telephone  : MUSEUM  4542. 


A CENTURY  OF  EXPERIENCE. 


V 


ADVERTISEMENTS 


JOHN  HADDON  & CO. 

SALISBURY  SQUARE,  FLEET  STREET,  E.C.4. 

Actual  Makers  of  Copper 
Plates  and  Presses  for 
Photogravure,  Etching, 
and  all  Kindred 
Processes. 


New  Design  Mangle  Gear  Copper  Plate 
Press  as  used  at  the  P ainters-Etchers’  Exhibition 

Smaller  Presses  for  Bench  also  stocked,  with  all 
Tools  and  Materials  used  by  the  Leading  Artists. 


ADVERTISEMENTS 


VI 


Photogravure  Machinery 

ROTARY  DUPLEX  MACHINES  with 
Sheet  Cutter  or  with  Folder. 

SINGLE  ROTARY  MACHINES  with 
Sheet  Cutting  Device  or  Re-Reel. 

PATENT  SHEET  FED  MACHINES,  to 
admit  Cylinders  of  various  sizes. 


NEW  PATENT  MODEL  PHOTOGRAVURE 
SHEET  FED  MACHINE 

Suitable  for  Printing  Illustrated  Catalogues, 
Memos,  Calendars,  &c.,  &c. 

A very  Useful  Machine,  Maximum  Size  of 
Sheet  rx\2'\ 

Any  Printer  can  produce  High  Class 
Photogravure  Prints  by  this  Machine. 

Send  Negative  Photo,  of  Subject  required, 
when  Etched  Copper  Plates  will  be  supplied 
at  Reasonable  Price  Ready  for  Printing. 

SIMPLE  TO  WORK. 

THE  LATEST  IN  PHOTOGRAVURE 

Apply  : 

PICKUP  & KNOWLES  LTD., 
Cobden  Street,  Pendleton, 
MANCHESTER. 


Vll 


ADVERTISEMENTS 


“ INKS  THAT  PRINT  WELL  ! ” 

R.  A.  Bartlett  & Earl, 

LIMITED. 

Managing  Director:  R.  A.  BARTLETT. 
Director  and  General  Manager:  A.  E.  EARL. 

Printing  Ink,  Varnish  and 
Colour  Manufacturers. 

SPECIMEN  BOOK  ON  APPLICATION. 

8,  HYTHE  ROAD,  N.W.HX 

Telephone:  3043  Willesden. 

The  House  for 
BEST  Photogravure  Inks. 

London  Sales  Manager : FRED.  H.  HOWE. 

Sole  Agents  for  “ P.  6t  B.”  Photogravure  Machine. 


♦ 


